What does it mean?

This generic powertrain/engine diagnostic code generally applies to all OBD-II equipped vehicles, including but not limited to Chevrolet, Acura, Honda, Saturn, Jeep, Toyota, etc.

The Transmission Fluid Pressure Sensor/Switch (TFPS) is typically found attached to the side of the valve body inside the transmission, although it may sometimes be found screwed into the side of the transmission case/body itself.

The TFPS converts mechanical transmission pressures into an electrical signal for the Powertrain Control Module (PCM) or Transmission Control Module (TCM). Typically, the PCM/TCM will then inform other controllers using the vehicle’s data communication bus.

The PCM/TCM receives this voltage signal to determine the transmission operating pressure or when a change occurs. This code is set if this “H” input does not match the normal operating voltages stored in the PCM/TCM memory. This may also be due to internal mechanical problems inside the transmission. Refer to a vehicle-specific repair manual to determine what the “H” circuit is for your particular vehicle.

P084C is typically an electrical circuit issue (TFPS sensor circuit). This cannot be ignored during the troubleshooting phase, especially when dealing with an intermittent problem.

Troubleshooting steps may vary depending on the manufacturer, TFPS sensor type, and wire colors.

Related Transmission Fluid Pressure Sensor “H” Circuit Codes:

• P084A Transmission Fluid Pressure Sensor/Switch “H”
• P084B Transmission Fluid Pressure Sensor/Switch “H” Circuit Range/Performance
• P084D Transmission Fluid Pressure Sensor/Switch “H” High
• P084E Transmission Fluid Pressure Sensor/Switch “H” Circuit Intermittent

Code Severity and Symptoms

Severity depends on which circuit the failure occurred in. Since this is an electrical failure, the PCM/TCM may compensate to some extent. The failure may mean the PCM/TCM alters transmission shifting if it is electronically controlled.

Symptoms of a P084C engine code may include:

• Malfunction Indicator Lamp illuminated
• Change in shift quality
• Vehicle starts in 2nd or 3rd gear (limp mode)

Causes

Typically, the causes for this code to set are:

• Short to ground in the signal circuit to the TFPS sensor – possible
• Failed/internally shorted TFPS sensor – probable
• Failed PCM – unlikely (programming required after replacement)

Diagnostic and Repair Procedures

A good starting point is always to check the Technical Service Bulletins (TSBs) for your particular vehicle. Your issue may be a known problem with a known fix published by the manufacturer and can save you time and money when diagnosing.

Next, locate the Transmission Fluid Pressure Sensor/Switch (TFPS) on your particular vehicle. The TFPS is typically found attached to the side of the valve body inside the transmission, although it is sometimes screwed into the side of the transmission case/body itself. Once located, visually inspect the connector and wiring. Look for chafing, rubbing, bare wires, burns, or melted plastic. Separate the connector and carefully inspect the terminals (the metal parts) inside the connector. See if they look burned or have a green tint indicating corrosion, especially if they are attached outside the transmission case. Use electrical contact cleaner and a plastic bristle brush if cleaning the terminals is necessary. Let it dry and apply electrical grease where the terminals make contact.

If you have a scan tool, clear the diagnostic codes from memory and see if the P084C code returns. If not, the connections were likely your problem.

This is the most common area of concern for this code, as external transmission connections have the highest number of corrosion issues.

If the P084C code returns, we will need to test the TFPS sensor and its associated circuits. With the key off, disconnect the electrical connector from the TFPS sensor. Connect a black wire from the digital voltmeter (DVOM) to the ground or low reference terminal at the TFPS sensor wiring harness connector. Connect the red wire from the digital voltmeter to the signal terminal at the TFPS sensor wiring harness connector. Turn the key to the engine off position. Check manufacturer specifications; the voltmeter should read 12 volts or 5 volts. Wiggle the connections to see if they change. If the voltage is incorrect, repair the power or ground cable or replace the PCM/TCM.

If the previous test was successful, connect one wire of an ohmmeter to the signal terminal of the TFPS sensor and the other wire to the ground or low reference terminal of the sensor. Check manufacturer specifications for sensor resistance to accurately test resistance to pressure when no pressure is applied to it. Wiggle the Transmission Fluid Pressure Sensor/Switch connector while monitoring the resistance. If the ohmmeter readings do not pass, replace the TFPS.

What does it mean?

This generic powertrain/engine diagnostic code generally applies to all OBD-II equipped vehicles, including but not limited to Dodge, Chrysler, Chevrolet, GMC, Acura, Toyota, etc.

The Transmission Fluid Pressure Sensor/Switch (TFPS) is typically found attached to the side of the valve body inside the transmission, although it may sometimes be found screwed into the side of the transmission case/body itself.

The TFPS converts mechanical transmission pressures into an electrical signal for the Powertrain Control Module (PCM) or Transmission Control Module (TCM). Typically, the PCM/TCM will then inform other controllers using the vehicle’s data communication bus.

The PCM/TCM receives this voltage signal to determine the transmission operating pressure or when a change occurs. This code is set if this “H” input does not match the normal operating voltages stored in the PCM/TCM memory. Refer to a vehicle-specific repair manual to determine what the “H” circuit is for your particular vehicle.

P084D is typically an electrical circuit issue (TFPS sensor circuit). This cannot be ignored in the troubleshooting phase, especially when it is an intermittent problem.

Troubleshooting steps may vary depending on the manufacturer, TFPS sensor type, and wire colors.

Related Transmission Fluid Pressure Sensor “H” Circuit Codes:

• P084A Transmission Fluid Pressure Sensor/Switch “H”
• P084B Transmission Fluid Pressure Sensor/Switch “H” Circuit Range/Performance
• P084C Transmission Fluid Pressure Sensor/Switch “H” Low
• P084E Transmission Fluid Pressure Sensor/Switch “H” Circuit Intermittent

Code Severity and Symptoms

The severity depends on the circuit where the failure occurred. Since it is an electrical failure, the PCM/TCM can compensate to some extent. The failure may mean the PCM/TCM alters the transmission shift if it is electronically controlled.

Symptoms of a P084D engine code may include:

Malfunction Indicator Light illuminated
Change in shift quality
Vehicle starts in 2nd or 3rd gear (limp mode)

Causes

Typically, the causes for this code to set are as follows:

• Short to power in the TFPS sensor signal circuit – possible
• Open circuit to ground of the TFPS sensor – possible
• Failed/internally shorted TFPS sensor – probable
• Failed PCM – unlikely (programming required after replacement)

Diagnostic and Repair Procedures

A good starting point is always to check the Technical Service Bulletins (TSBs) for your particular vehicle. Your issue may be a known problem with a known fix released by the manufacturer and can save you time and money when diagnosing.

A good example of this would be if there are known power-related codes with P084D, or if there is more than one pressure sensor/switch code. If so, begin your diagnosis with the power-related trouble code or multiple code diagnosis first, as this may be the reason for P084D.

Next, locate the Transmission Fluid Pressure Sensor/Switch (TFPS) on your particular vehicle. The TFPS is typically found attached to the side of the valve body inside the transmission, although it is sometimes screwed into the side of the transmission case/body itself. Once located, visually inspect the connector and wiring. Look for chafing, rubbing, bare wires, burns, or melted plastic. Disconnect the connector and carefully inspect the terminals (the metal parts) inside the connector. See if they look burned or have a green tint indicating corrosion, especially if they are attached outside the transmission case. Use electrical contact cleaner and a plastic bristle brush if cleaning the terminals is necessary. Let it dry and apply electrical grease where the terminals make contact.

If you have a scan tool, clear the diagnostic codes from memory and see if the P084D code returns. If not, the connections were likely your problem.

This is the most common area of concern for this code, as external transmission connections have the highest number of corrosion issues.

If the P084D code returns, we will need to test the TFPS sensor and its associated circuits. With the key off, disconnect the electrical connector from the TFPS sensor. Connect a black wire from the Digital Volt Ohm Meter (DVOM) to the ground or low reference terminal at the TFPS sensor wiring harness connector. Connect the red wire from the DVOM to the signal terminal at the TFPS sensor wiring harness connector. Turn the key to the engine off position. Check manufacturer specifications; the voltmeter should read 12 volts or 5 volts. Wiggle the connections to see if they change. If the voltage is incorrect, repair the power or ground wire or replace the PCM/TCM.

If the previous test was successful, connect one wire of an ohmmeter to the signal terminal of the TFPS sensor and the other wire to the ground or low reference terminal at the sensor. Check manufacturer specifications for sensor resistance to accurately test the resistance to pressure when no pressure is applied to it. Wiggle the Transmission Fluid Pressure Sensor/Switch connector while monitoring the resistance. If the ohmmeter readings do not pass, replace the TFPS.

If all previous tests have passed and you continue to get a P084D, this would most likely indicate a faulty TFPS sensor, although a faulty PCM/TCM cannot be ruled out, nor can internal transmission malfunctions until the TFPS sensor has been replaced. If in doubt, seek assistance from a qualified automotive diagnostician. PCMs/TCMs need to be programmed or calibrated to the vehicle in order to be installed correctly.

What does it mean?

This generic powertrain/engine diagnostic code generally applies to all vehicles equipped with OBD-II (e.g., GM, Chevrolet, Honda, Toyota, Ford, etc.), but appears more frequently in Nissan vehicles.

The Transmission Fluid Pressure Sensor/Switch (TFPS) is typically found attached to the side of the valve body inside the transmission, although it may sometimes be found screwed into the side of the transmission case/body itself.

The TFPS converts mechanical transmission pressures into an electrical signal for the Powertrain Control Module (PCM) or Transmission Control Module (TCM). Typically, the PCM/TCM will then inform other controllers using the vehicle’s data communication bus.

The PCM/TCM receives this voltage signal to determine the transmission operating pressure or when a change occurs. This code is set if this “H” input does not match the normal operating voltages stored in the PCM/TCM memory. This can also be due to internal mechanical issues within the transmission. Refer to a vehicle-specific repair manual to determine what the “H” circuit is for your particular vehicle.

P084E is generally an electrical circuit issue (TFPS sensor circuit), although, as mentioned earlier, this code can also be set due to mechanical problems (internal leaks, cracked or missing check balls in the valve body, low system operating pressure/main line pressure, stuck valve in the valve body). This cannot be ignored during the troubleshooting phase, especially when dealing with an intermittent issue.

Troubleshooting steps may vary by manufacturer, TFPS sensor type, and wire colors.

Related Transmission Fluid Pressure Sensor “H” Circuit Codes:

• P084A Transmission Fluid Pressure Sensor/Switch “H”
• P084B Transmission Fluid Pressure Sensor/Switch “H” Circuit Range/Performance
• P084C Transmission Fluid Pressure Sensor/Switch “H” Low
• P084D Transmission Fluid Pressure Sensor/Switch “H” High

Code Severity and Symptoms

The severity depends on the circuit where the failure occurred. Since it could be an electrical failure or a mechanical failure, the PCM/TCM may compensate to some extent. The failure could mean the PCM/TCM alters the transmission shift if it is electronically controlled.

Symptoms of a P084E engine code may include:

• Malfunction Indicator Lamp illuminated
• Change in shift quality
• Vehicle starts in 2nd or 3rd gear (limp mode)

Causes

Typically, the causes for this code to set are as follows:

Intermittent open in the signal circuit to the TFPS sensor
Intermittent short to voltage in the signal circuit to the TFPS sensor
Intermittent short to ground in the signal circuit to the TFPS sensor
Failed TFPS sensor – likely
Internal transmission mechanical issue – possible
Failed PCM – unlikely (programming required after replacement)

Diagnostic and Repair Procedures

A good starting point is always to check the Technical Service Bulletins (TSBs) for your specific vehicle. Your issue may be a known problem with a known fix published by the manufacturer and can save you time and money during diagnosis.

A good example of this would be if there are known power-related codes with P084E, or if there is more than one pressure sensor/switch code. If so, begin your diagnosis with the power-related fault code or multiple code diagnostics first, as this may be the reason for P084E.

Next, locate the Transmission Fluid Pressure Sensor/Switch (TFPS) on your specific vehicle. The TFPS is typically found attached to the side of the valve body inside the transmission, although it is sometimes screwed into the side of the transmission case/body itself. Once located, visually inspect the connector and wiring. Look for chafing, rubbing, bare wires, burns, or melted plastic. Disconnect the connector and carefully inspect the terminals (the metal parts) inside the connector. See if they appear burned or have a greenish tint indicating corrosion, especially if they are mounted outside the transmission case. Use electrical contact cleaner and a plastic bristle brush if cleaning the terminals is necessary. Let it dry and apply electrical grease where the terminals make contact.

If you have a scan tool, clear the diagnostic codes from memory and see if the P084E code returns. If it does not, the connections were likely your problem.

This is the most common area of concern for this code, as external transmission connections have the highest incidence of corrosion issues.

If the P084E code returns, we will need to test the TFPS sensor and its associated circuits. With the key off, disconnect the electrical connector from the TFPS sensor. Connect a black wire from the Digital Volt Ohm Meter (DVOM) to the ground or low reference terminal at the TFPS sensor harness connector. Connect the red wire from the DVOM to the signal terminal at the TFPS sensor harness connector. Turn the key to the engine off position. Check the manufacturer’s specifications; the voltmeter should read 12 volts or 5 volts. Wiggle the connections to see if they change. If the voltage is incorrect, repair the power or ground wire or replace the PCM/TCM.

If the previous test was successful, connect one wire of an ohmmeter to the signal terminal of the TFPS sensor and the other wire to the ground or low reference terminal of the sensor. Check the manufacturer’s specifications for the sensor’s resistance to accurately test the resistance to pressure when no pressure is applied to it. Wiggle the Transmission Fluid Pressure Sensor/Switch connector while monitoring the resistance. If the ohmmeter readings do not pass, replace the TFPS.

If all previous tests were successful and you continue to get a P084E, this would most likely indicate a faulty TFPS sensor, although a faulty PCM/TCM cannot be ruled out, nor can internal transmission malfunctions until the TFPS sensor has been replaced. If in doubt, seek assistance from a qualified automotive diagnostician. PCMs/TCMs need to be programmed or calibrated to the vehicle to be installed correctly.

P084F Possible Causes

• Faulty park/neutral switch
• Park/neutral switch harness is open or shorted
• Poor electrical connection in the park/neutral switch circuit

What Does It Mean?

First Diagnose Code P084F

Check the “Possible Causes” listed above. Visually inspect the related wiring harness and connectors. Look for damaged components and check for broken, bent, pushed out, or corroded connector pins.

P084F Possible Symptoms

Check engine light illuminated (or service engine soon warning light)

P084F Description

The Transmission Control Module (TCM) monitors the output signal from the park/neutral switch. The TCM sets the OBDII code when the park/neutral switch output does not meet factory specifications.
OBDII Code P084F – Park/Neutral Switch Output Circuit

Definition of Code P0850

If the PCM has stored code P0850, it means that the input circuit measuring the function of the park/neutral switch has provided an abnormal voltage reading.
What does code P0850 mean

When the vehicle is put into park or neutral, voltage readings are sent to the PCM from a variety of sensors and components. This data helps the PCM ensure that park or neutral has been engaged and that the vehicle is operating correctly. If the voltage reading from the park/neutral switch input circuit does not match the manufacturer’s specifications, the PCM will store code P0850. This code only applies to vehicles equipped with both an automatic transmission and a four-wheel drive system.

What causes code P0850?

In the majority of cases, code P0850 is caused by a misadjusted transfer case range sensor. This may have been improperly installed during a previous repair.

Other causes may include:

• Faulty park/neutral switch
• Open or shorted park/neutral switch harness
• Poor electrical connection in the park/neutral switch circuit
• Faulty range sensor
• Damaged wiring or other electrical components
• Improperly installed sensor retaining bolts
• Excessively corroded sensor connector

What are the symptoms of code P0850?

In addition to the Check Engine light illuminating, vehicle owners may observe symptoms such as the inability to engage four-wheel drive, harsh shifting or complete failure to shift, and decreased fuel economy.
How does a mechanic diagnose code P0850?

The first step is to verify the code with an OBD-II scanner. Once that is done, the mechanic should begin with a visual inspection of all electrical components, including wiring and connectors. Repair or replace parts as necessary, then clear the code from the PCM and retest the system. If the code returns, the next step is to check battery voltage and ground signals at the park/neutral switch.

Throughout the diagnostic process, the mechanic should compare readings to the manufacturer’s specifications. If the readings are within the acceptable range, then suspect the sensor itself is faulty; if the readings are not within the acceptable range, further repairs will need to be attempted. Remember to clear the code and retest the system after each potential repair, to ensure the correct fix is identified and you are not wasting time performing unnecessary repairs.
Common mistakes when diagnosing code P0850

The most common diagnostic error is blaming a faulty transfer case range sensor, when in fact the part was not defective, but simply misadjusted.

How severe is code P0850?

Since this code relates directly to the vehicle’s drivability, it is considered a significant issue that must be addressed immediately. Failure to repair code P0850 could create dangerous driving conditions and lead to larger, more costly repairs. When code P0850 is detected, it is best to have an automotive technician address the problem right away.

What repairs can fix code P0850?

There are many ways for a technician to address a code P0850 detection. They include:

• Adjusting the transfer case range sensor
• Replacing the faulty park/neutral switch
• Repairing the open or shorted park/neutral switch harness
• Repairing a poor electrical connection in the park/neutral switch circuit
• Replacing the faulty range sensor
• Replacing damaged wiring or other electrical components
• Properly installing the sensor retaining bolts
• Replacing the excessively corroded sensor connector

P0851 Possible Causes

    Faulty Park/Neutral Switch
    Park/Neutral Switch harness is open or shorted
    Poor electrical connection in Park/Neutral Switch circuit

What Does It Mean?

How to Fix Code P0851

    Check the “Possible Causes” listed above. Visually inspect the related wiring harness and connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector pins.

P0851 Possible Symptoms

    Engine Light On (or Service Engine Soon Warning Light)

P0851 Meaning

The Manual Transmission Shift Shaft Switch Assembly, also known as the Internal Mode Switch (IMS), is a sliding contact switch attached to the manual transmission shift shaft inside the transmission case. The Park/Neutral Position (PNP) switch is integrated into the IMS and connects to the Transmission Control Module (TCM) chassis via a short wiring harness. The 5 TCM inputs from the transmission manual shift shaft switch assembly indicate the transmission gear selector lever position. This information is used for engine start enable, engine controls, and to determine transmission shift patterns. The status of each input can be displayed on the scan tool. The five represented input parameters are Signal A, Signal B, Signal C, Signal P (parity), and Signal N (Park/Neutral start signal). The Park/Neutral signal is sent from the Park/Neutral switch directly to the Engine Control Module (ECM) and is used for engine start enable. The Park/Neutral signal circuit is not internally connected to the TCM; the circuit uses the TCM as an intercommunication connector only. The ECM Park/Neutral diagnostic monitors the Park/Neutral signal circuit for low voltage when the ECM expects to see high voltage and high voltage when the ECM expects to see low voltage.

P0852 Possible Causes

    Faulty Park/Neutral Switch
    Park/Neutral Switch harness is open or shorted
    Poor electrical connection in Park/Neutral Switch circuit

What Does It Mean?

How to Fix Code P0852

    Check the “Possible Causes” listed above. Visually inspect the related wiring harness and connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector pins.

P0852 Possible Symptoms

    Check Engine Light illuminated (or Service Engine Soon warning light)

P0852 Meaning

The Manual Transmission Shift Shaft Switch Assembly, also known as the Internal Mode Switch (IMS), is a sliding contact switch attached to the manual transmission shift shaft inside the transmission case. The Park/Neutral Position (PNP) switch is integrated into the IMS and connects to the Transmission Control Module (TCM) chassis via a short wiring harness. The 5 TCM inputs from the transmission manual shift shaft switch assembly indicate the transmission gear selector lever position. This information is used for engine start enable, engine controls, and to determine transmission shift patterns. The status of each input can be displayed on the scan tool. The five represented input parameters are Signal A, Signal B, Signal C, Signal P (parity), and Signal N (Park/Neutral start signal). The Park/Neutral signal is sent from the Park/Neutral switch directly to the Engine Control Module (ECM) and is used for engine start enable. The Park/Neutral signal circuit is not internally connected to the TCM; the circuit uses the TCM as an intercommunication connector only. The ECM Park/Neutral diagnostic monitors the Park/Neutral signal circuit for low voltage when the ECM expects to see high voltage and high voltage when the ECM expects to see low voltage.

P0853 Possible Causes

     Faulty drive switch
     Drive switch harness is open or short-circuited
     Poor electrical connection of the control switch circuit
 

What Does It Mean?

How to Fix Code P0853

     Check the “Possible Causes” listed above. Visually inspect the cable harness and associated connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector pins.

P0853 Possible Symptoms

     Engine light on (or service engine soon warning light)

P0853 Meaning

The Transmission Control Module (TCM) monitors the signal from the drive switch. The TCM sets the OBDII code when the control switch does not meet factory specifications.
OBDII Code P0853 – Control Switch Input Circuit

Definition of Code P0854

Code P0854 is a generic powertrain code related to the transmission, including pressure faults and sensor failures. In this case, the Engine Control Module (ECM) receives a voltage signal from the drive switch input that is below the predefined allowable parameters.

Related codes to P0854 include:

• P0850: Park/Neutral Switch Input Circuit
• P0851: Park/Neutral Switch Input Circuit Low
• P0852: Park/Neutral Switch Input Circuit High
• P0853: Drive Switch Input Circuit
• P0855: Drive Switch Input Circuit High

What does code P0854 mean?

A code P0854 is stored when the ECM has detected a fault or malfunction in the drive switch input circuit. This code will only apply to vehicles equipped with four-wheel drive and an automatic transmission.

The drive switch is the device that tells the ECM which gear the transfer case is in, and most drive switches are variable resistance. The switch is located above the transfer case shift shaft, and the shift lever will slide over it. When the shift lever is moved, the range sensor pivot hits different contacts. These contacts send voltage levels to the ECM and help it determine shift strategy and more.

The vehicle’s transfer case shift selector range sensor sends data to the ECM, which uses the data to calculate engine timing, etc. If the ECM receives data from sensors such as vehicle speed or transmission shift solenoids indicating that the vehicle is below the correct shift range, code P0854 may be stored.

What causes code P0854?

Several issues can cause a code P0854, including:

• Misadjusted transfer case range sensor
• Faulty or damaged transfer case range sensor
• Damaged, open, shorted, or corroded electrical wiring
• Corrosion in the sensor connector
• Damaged or faulty drive switch

What are the symptoms of code P0854?

Symptoms of a code P0854 may include:

• An engine warning or check engine light may illuminate
• Four-wheel drive may not engage
• The vehicle may jerk when moving
• The vehicle may not move at all
• Reduced fuel economy
• The vehicle may enter “limp” mode

How does a mechanic diagnose code P0854?

• A mechanic may use several methods to diagnose a P0854 fault code, including:
• Using an OBD-II scanner to check for a stored P0854 fault code
• Visually inspecting the system’s wiring and connectors for visible signs of damage or corrosion
• Checking the drive switch for battery voltage and ground signals
• If battery voltage or ground signals are open, check continuity and resistance in both circuits with a digital volt/ohmmeter
• Test all associated circuits and the sensor for resistance and continuity, and compare with manufacturer recommendations

Common mistakes when diagnosing code P0854

Sometimes, the transfer case range sensor may be incorrectly identified as the problem and replaced, when there may be a simple alignment adjustment that could resolve the issue.

How severe is code P0854?

Since safely operating a vehicle may be affected due to faults that store a P0854 code, this code is considered potentially serious. When this code appears, it is recommended to bring your vehicle to your local service center or a mechanic immediately for repair and diagnosis.

What repairs can fix code P0854?

• Several repairs can correct a P0854 fault code and include:
• Repairing or replacing damaged system wiring and connectors
• Retest the system and continue repairing any damaged or faulty wiring
• Replace the damaged or faulty drive switch
• Replace the damaged transfer case range sensor
• Clear all codes, test the vehicle, and rescan to see if any codes reappear

Additional comments to consider regarding code P0854

It is recommended to always diagnose and repair fault codes in the order they appear, especially when related to electrical wiring and sensor faults, as subsequent codes could be symptoms of a code higher in the list.

P0855 Possible Causes

• Faulty drive switch
• Drive switch harness is open or short-circuited
• Poor electrical connection in the control switch circuit

What does it mean?

First diagnose code P0855

Check the “possible causes” listed above. Visually inspect the cable harness and associated connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector pins.

P0855 Possible Symptoms

Check engine light on (or service engine soon warning light)

P0855 Description

The Transmission Control Module (TCM) monitors the signal from the drive switch. The TCM sets the OBDII code when the control switch does not meet factory specifications.
OBDII Code P0855 – Drive Switch Input Circuit High – AutoCodes.com