P2085 Exhaust Gas Temperature EGT Sensor Circuit Intermittent, Bank 1 Sensor 2

Symptoms

The check engine light will illuminate and the computer will have set code P2085. No other symptoms will be easily noticeable.

Potential Causes

Causes

of this DTC may include:

Check for loose or corroded connectors or terminals, which is often the case
Broken wires or missing insulation can cause a direct short to ground
The sensor may have failed
A catback exhaust system without EGT provisions installed
It is possible, but unlikely, that the computer has failed

P2085 Repair Procedures

Lift the vehicle and locate the sensor. For this code, it refers to the Bank 1 sensor, which is the engine side containing cylinder #1. It is located between the exhaust manifold and the converter, or in the case of a diesel, before the diesel particulate filter (DPF). It looks different from oxygen sensors in that it is only a two-wire plug. A vehicle with a turbo will have the sensor near the turbo’s exhaust inlet.
Check the connectors for any abnormalities such as corrosion or loose terminals. Follow the pigtail to its connector and check it as well.
Look for signs of missing insulation or bare wires that could be shorted to ground.
Disconnect the upper connector and remove the EGT sensor. Check the resistance with an ohmmeter. Probe the two terminals of the connector. A good EGT will have about 150 ohms. If there is very little resistance—below 50 ohms, replace the sensor.
Use a hairdryer or heat gun and heat the sensor while watching the ohmmeter. The resistance should decrease as the sensor heats up and increase as it cools. If not, replace it.
If everything was good at this point, turn on the key and measure the voltage on the engine side of the pigtail. There should be 5 volts at the connector. If not, replace the computer.
Another reason this code may be set is if the catalytic converter has been replaced with a catback system. In most states, this is an illegal procedure subject to heavy fines if caught. It is advisable to check local and national laws regarding the removal of this system as it allows uncontrolled emissions into the atmosphere. It may work, but it is everyone’s responsibility to do our part to keep our atmosphere clean for future generations.

Until this is repaired, the code can be reset by purchasing a 2.2 ohm resistor for pocket change at any electronics store. Simply discard the EGT sensor and plug the resistor into the engine-side electrical connector. Wrap it with tape and the computer will be convinced that the EGT is functioning properly.

P2086 Exhaust Gas Temperature Sensor Circuit Range/Performance, Bank 2 Sensor 2

Symptoms

The check engine light will illuminate and the computer will have set code P2086. No other symptoms will be easily noticeable.

Potential Causes

Causes of this DTC may include:

Check for loose or corroded connectors or terminals, which is often the case
Broken wires or missing insulation can cause a direct short to ground
The sensor may have failed
A catback exhaust system without EGT provisions installed
It is possible, but unlikely, that the computer has failed

P2086 Repair Procedures

Lift the vehicle and locate the sensor. For this code, it refers to the Bank 1 sensor, which is the engine side containing cylinder #1. It is located between the exhaust manifold and the converter, or in the case of a diesel, before the diesel particulate filter (DPF). It looks different from oxygen sensors in that it is only a two-wire plug. A vehicle with a turbo will have the sensor near the turbo’s exhaust inlet.
Check the connectors for any abnormalities such as corrosion or loose terminals. Follow the pigtail to its connector and check it as well.
Look for signs of missing insulation or exposed wires that could be shorted to ground.
Disconnect the upper connector and remove the EGT sensor. Check the resistance with an ohmmeter. Probe the two terminals of the connector. A good EGT will have about 150 ohms. If there is very little resistance—below 50 ohms, replace the sensor.
Use a hairdryer or heat gun and heat the sensor while watching the ohmmeter. The resistance should decrease as the sensor heats up and increase as it cools. If not, replace it.
If everything was good at this point, turn on the key and measure the voltage on the engine side of the pigtail. There should be 5 volts at the connector. If not, replace the computer.
Another reason this code may be set is if the catalytic converter has been replaced in favor of a catback system. In most states, this is an illegal procedure subject to heavy fines if caught. It is advisable to check local and national laws regarding the removal of this system as it allows uncontrolled emissions into the atmosphere. It may work, but it is everyone’s responsibility to do our part to keep our atmosphere clean for future generations.

P2087 Exhaust Gas Temperature EGT Sensor Circuit Intermittent Bank 2 Sensor 2

Symptoms

The check engine light will illuminate and the computer will have set code P2087. No other symptoms will be easily noticeable.

Potential Causes

Causes

of this DTC may include:

Check for loose or corroded connectors or terminals, which is often the case
Broken wires or missing insulation can cause a direct short to ground
The sensor may have failed
A catback exhaust system without EGT provisions installed
It is possible, but unlikely, that the computer has failed

P2087 Repair Procedures

Lift the vehicle and locate the sensor. For this code, it refers to the Bank 1 sensor, which is the engine side containing cylinder #1. It is located between the exhaust manifold and the converter or, in the case of a diesel, before the diesel particulate filter (DPF). It looks different from oxygen sensors in that it is only a two-wire plug. A vehicle with a turbo will have the sensor near the turbo’s exhaust inlet.
Check the connectors for any abnormalities such as corrosion or loose terminals. Follow the pigtail to its connector and check it as well.
Look for signs of missing insulation or exposed wires that could be shorted to ground.
Disconnect the upstream connector and remove the EGT sensor. Check the resistance with an ohmmeter. Probe the two terminals of the connector. A good EGT will have about 150 ohms. If there is very little resistance—below 50 ohms, replace the sensor.
Use a hairdryer or heat gun and heat the sensor while watching the ohmmeter. The resistance should decrease as the sensor heats up and increase as it cools. If not, replace it.
If everything was good at this point, turn on the key and measure the voltage on the engine side of the pigtail. There should be 5 volts at the connector. If not, replace the computer.
Another reason this code may be set is if the catalytic converter has been replaced in favor of a catback system. In most states, this is an illegal procedure subject to heavy fines if caught. It is advisable to check local and national laws regarding the removal of this system as it allows uncontrolled emissions into the atmosphere. It may work, but it is everyone’s responsibility to do our part to keep our atmosphere clean for future generations.

Until this is repaired, the code can be reset by purchasing a 2.2-ohm resistor for pocket change at any electronics store. Simply discard the EGT sensor and plug the resistor into the engine-side electrical connector. Wrap it with tape, and the computer will be convinced that the EGT is functioning properly.

P2088 A, Camshaft Position Actuator Control Circuit, Bank 1

Fault Severity

The severity of P2088 varies significantly:

Mild Scenario: Engine light on, vehicle operational.
Critical Scenario: Engine stalling, failure to start, or risks of internal damage (especially if caused by a faulty timing chain/belt).

Conclusion: Always requires prompt diagnosis, especially if accompanied by pronounced engine symptoms.

Common Symptoms

Irregular idle or misfires
Reduced performance and increased fuel consumption
“Change Oil” or “Service Required” signal activated
Engine light on
Abnormally low oil pressure

Main Causes

Category	Faulty Components
Timing System	Worn belt/chain, misaligned components
VVT System	Failed variable timing solenoid or actuator
Lubrication	Oil level too low, degraded oil
Electrical	Blown fuse, damaged wiring, corroded connectors
Engine Control	ECU failure

Diagnostic Procedure

Required Equipment:

OBD2 scanner, digital multimeter
Vehicle technical documentation (+ TSB)
Oil pressure gauge (ideal)

Key Steps:

Check TSBs
- Review manufacturer Technical Service Bulletins for known solutions related to model/engine.
Preliminary Checks (mandatory)
- Engine oil level and condition 🛢️
- Visual inspection: wiring, connectors (corrosion, exposed wires), VVT components.
Advanced Checks
- Timing Alignment: Check alignment with a dedicated tool (misalignment = common cause).
- Oil Pressure: Measure with a pressure gauge (target: manufacturer specifications).
- Electrical Circuits:
  - Test power supply voltage (5V) and ground of camshaft/crankshaft sensors.
  - Check wire continuity (power off, resistance ≈ 0 Ω).
Final Diagnosis
- If electrical anomalies: Repair wires or replace connectors.
- If incorrect timing: Check belt/chain and sprockets.
- If low oil pressure: Look for leaks or faulty pump.

Common Repairs

Replacing VVT solenoid/actuator
Changing timing belt/chain and realignment
Cleaning connectors or replacing wiring
Oil change + filter
ECU replacement (as a last resort ⚠️)

Pitfall to Avoid: Do not replace the ECU or sensors without ruling out:

A timing issue

Low oil pressure

A faulty fuse/wiring

Final Note:
Manufacturer data always takes precedence over this article. A methodical diagnosis (simple → complex) avoids unnecessary costly repairs.

Improvements Made:

Information Structuring:
- Table for causes
- Progressive diagnostic steps (basic → advanced)
Explicit Warnings:
- Highlighted box on the risk of incorrectly replacing the ECU
- Emphasis on oil pressure and timing as priorities
Precise Technical Language:
- Standardized terms (VVT, ECU, TSB)
- Detailed electrical testing procedures (5V, continuity, Ω)
Removal of Redundancies:
- Grouping of related symptoms (performance/consumption)
- Merged “wiring” and “connectors” causes
Visibility of Critical Points:
- Visual symbols (⚠️, 🛢️) to alert the reader
- Concise phrasing in control steps (“power off”)

P2089 High Control Circuit for Camshaft Position Actuator, Bank 1

How severe is this DTC?

The severity of this code can vary greatly from a simple check engine light on a vehicle that starts and runs to an automobile that will idle roughly or not start at all. The code can be serious depending on the symptoms present. If the code is caused by a faulty timing chain or belt, the result can be internal engine damage.

What are some of the symptoms of the code?

Symptoms of a P2089 fault code may include:

Irregular engine idle
Decreased oil pressure
Engine may misfire
Poor engine performance
Increased fuel consumption
Change oil or service soon light is on
Check engine light on

What are some common causes of the code?

Causes of this P2089 code may include:

Worn timing belt or chain
Faulty camshaft variable timing solenoid
Defective variable valve timing actuator
Engine oil level too low
Blown fuse or fuse link (if applicable)
Misaligned timing components
Corroded or damaged connector
Faulty or damaged wiring
Faulty ECU

What are the troubleshooting steps for P2089?

The first step in the troubleshooting process for any malfunction is to search for Technical Service Bulletins (TSBs) for the specific vehicle by year, model, and engine combination. In some circumstances, this can save you a lot of time in the long run by pointing you in the right direction.

The second step is to check the oil level and condition. Proper oil pressure plays a key role in the operation of this circuit. Then, locate all components in this circuit and perform a thorough visual inspection to check the associated wiring for obvious defects such as scraping, rubbing, bare wires, or burns. Next, check the connectors for security, corrosion, and damaged pins. This process should include all related sensors, components, and control unit.

Advanced Steps

Advanced steps become very vehicle-specific and require appropriate advanced equipment to perform accurately. These procedures require a digital multimeter and vehicle-specific technical references. Other ideal tools for this situation are a timing light and an oil pressure gauge. Voltage requirements vary depending on the specific year and model of the vehicle.

Timing Checks

Timing must be checked using the appropriate testing equipment and adjustments must be precise for the engine to run properly. An incorrect timing reading indicates that essential timing components such as the belt, chain, or gears may be worn or damaged. If this code appears immediately after replacing a timing belt or chain, you may suspect improper alignment of timing components as a possible cause.

Voltage Checks

Camshaft and crankshaft sensors are typically supplied with a reference voltage of approximately 5 volts from the ECU.

If this process identifies the absence of a power source or ground, continuity tests may be required to verify the integrity of the wiring, connectors, and other components. Continuity tests should always be performed with the power disconnected from the circuit, and normal readings for wiring and connections should be 0 ohms of resistance. Resistance or lack of continuity is an indication of faulty wiring that is open or shorted and must be repaired or replaced.

What are the common repairs for this code?

Replacement of the camshaft variable timing solenoid
Replacement of the variable valve timing actuator
Replacement of the blown fuse or fuse link (if applicable)
Cleaning corrosion from connectors
Repairing or replacing faulty wiring
Changing oil and filter
Replacing the timing belt or chain
Replacing the ECU

Common mistakes may include:

Replacing the ECU or sensors is often done in error when poor timing alignment or insufficient oil pressure is the problem.

I hope the information in this article has been helpful in guiding you in the right direction to correct the issue with the camshaft position actuator control circuit error code. This article is strictly informational, and the technical data and service bulletins specific to your vehicle should always take priority.

P208A – Reductant Pump Control Circuit / Open

Code Severity: High (Critical)

This code indicates a major malfunction in the emissions reduction system. Ignoring P208A leads to:

🛑 Progressive immobilization (limp mode after 5-10 start cycles).
⚠️ Exceeding pollutant emission limits (risk of legal non-compliance).
💸 Costly damage to the SCR catalyst or other components.

Technical Meaning

Code P208A signals a problem in the reductant pump (DEF/AdBlue) control circuit. This pump is the heart of the SCR system:

Integrated functions:
- Diaphragm pump generating a pressure of 73 psi (500 kPa).
- Pressure sensor, purge valve, filter, internal heater.
Critical process:
- During injection: the pump fills the rail and purges air.
- At shutdown: purges DEF back to the tank to prevent freezing.
- Heater activated below -11°C to maintain fluidity.
Detected fault:
- The PCM (Powertrain Control Module) detects an electrical or mechanical anomaly in the pump circuit.

Possible Symptoms

🔶 Check Engine light on.
⚠️ DEF/SCR warning message on the dashboard.
🐌 Loss of engine power (limp mode activated).
💨 Excessive exhaust smoke (untreated NOx).
🔋 Battery drain (if pump is stuck running).

Possible Causes (Ranked by Frequency)

Rank	Cause	Technical Details
1	DEF pump failure	Pump seized, worn diaphragms, electric motor failure (most common cause).
2	Wiring problems	Cut/chafed wires, short circuit (±12V/ground), corrosion on connectors.
3	Faulty connectors	Oxidized, bent, improperly seated pins, or damaged seals.
4	Faulty power supply	Blown fuse, defective relay, or interrupted PCM power circuit.
5	PCM fault	Rare: software or hardware failure of the control module.

Diagnostic Procedure (Key Steps)

Required Tools: Multimeter, Advanced OBD2 Scanner (for reading DEF data), vehicle documentation.

Reading Codes & Live Data:
- Use a scanner to:
  - Read associated sub-codes (e.g., P208A-00, P208A-01…).
  - Analyze real-time data: DEF pressure, pump status, temperature.
Basic Electrical Checks:
- Fuse/Relay: Check the power supply circuit (refer to workshop manual).
- Pump Resistance:
```
Expected values: 0.5 - 5 Ω (out of specification = pump failure).
```
- Supply Voltage: Measure at the pump connector (ignition ON):
```
Expect 12V on positive pin; continuity to ground on negative pin.
```
Physical Inspection:
- Wiring: Follow the harness along its entire length (look for chafing, crushing).
- Connectors: Clean with electrical contact cleaner, check seals.
- Pump/Flow: Listen for the pump “hum” at startup (absence indicates failure).
Operational Test:
- Force pump activation via scanner (“Component Test”).
- Check DEF pressure (target: 73 psi). If zero: pump or purge valve failure.

Repair

✅ Defective pump: Replace the complete pump and module assembly (do not repair).
✅ Damaged wiring: Repair using waterproof connectors (solder + heat shrink tubing).
✅ Corroded connectors: Clean or replace the connector housing.
✅ Blown Fuse/Defective Relay: Identify the cause of the short circuit before replacement.

⚠️ Precautions:

Disconnect the battery before working.
Wear safety glasses/gloves (DEF is corrosive).
Purge residual pressure via scanner before disassembly.
Follow manufacturer procedure for air purge after repair.

Post-Repair Best Practices

Reset DEF adaptations via scanner.
Perform a complete drive cycle (15-20 km) for system recalibration.
Check for absence of leaks and return to normal pressures.

⚠️ Important: This code often requires professional intervention. If you are not equipped to test pressure or access PCM data, entrust the vehicle to a specialized workshop.

P208B – Range/Performance of Reducer Pump Control

P208B Possible Causes

Faulty reductant pump
Reductant pump harness is open or shorted
Reductant pump electrical circuit poor electrical connection

What Does It Mean?

How to Fix Code P208B

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.

P208B Possible Symptoms

Illuminated engine light (or service engine soon warning light)

P208B Meaning

The reductant pump assembly contains a diaphragm pressure pump, pressure sensor, purge valve, outlet filter, and internal heating element. The reductant pressure sensor provides feedback to the Powertrain Control Module (PCM), which regulates system pressure by controlling pump speed using pulse width modulation. When the PCM requests reductant injection, the reductant injector opens and the pump operates, filling the reductant pressure line and injector while purging air from the system. Once all air is purged, the injector closes and the pump increases pressure to 73 psi (500 kPa). The system is then primed and the injector supplies DEF to the SCR catalyst as determined by the PCM.
When the vehicle is shut down, the PCM closes the injector and activates the reductant purge valve, causing the pump to reverse flow and purge pressure from the reductant pressure line. The PCM then opens the injector to allow gas into the reductant pressure line, enabling the pump to purge any remaining DEF from the system and return it to the reductant tank. The PCM closes the injector and returns the purge valve to its forward position. The PCM commands the glow plug control module to provide voltage to the reductant pump assembly’s internal heating element when reductant temperature approaches 12°F (-11°C)….

P208C – Reductant Pump Control Circuit Low

P208C Possible Causes

Faulty reductant pump
Reductant pump harness is open or shorted
Reductant pump electrical circuit poor electrical connection

What Does It Mean?

How to Fix Code P208C

P208C Possible Symptoms

Illuminated engine light (or service engine soon warning light)

P208C Meaning

The reductant pump assembly contains a diaphragm pressure pump, a pressure sensor, a purge valve, an outlet filter, and an internal heating element. The reductant pressure sensor provides feedback to the powertrain control module (PCM), which regulates system pressure by controlling pump speed using pulse width modulation. When the PCM requests reductant injection, the reductant injector opens and the pump operates, filling the reductant pressure line and injector while purging air from the system. Once all air is purged, the injector closes and the pump increases pressure to 73 psi (500 kPa). The system is then primed and the injector supplies DEF to the SCR catalyst as determined by the PCM.

When the vehicle is stopped, the PCM closes the injector and activates the reductant purge valve, causing the pump to reverse flow and purge pressure from the reductant pressure line. The PCM then opens the injector to allow gas into the reductant pressure line, enabling the pump to purge any remaining DEF from the system and return it to the reductant tank. The PCM closes the injector and returns the purge valve to its forward position. The PCM commands the glow plug control module to provide voltage to the reductant pump assembly’s internal heating element when the reductant temperature approaches 12°F (-11°C).

P208D – High Reduction Pump Control Circuit

P208D Possible Causes

Faulty reductant pump
Reductant pump harness is open or shorted
Reductant pump electrical circuit poor electrical connection

What Does It Mean?

How to Fix Code P208D

P208D Possible Symptoms

Illuminated engine light (or service engine soon warning light)

P208D Meaning

When the vehicle is stopped, the PCM closes the injector and activates the reductant purge valve, causing the pump to reverse flow and purge pressure from the reductant pressure line. The PCM then opens the injector to allow gas into the reductant pressure line, enabling the pump to purge all remaining DEF from the system and return it to the reductant tank. The PCM closes the injector and returns the purge valve to its default position. The PCM commands the glow plug control module to provide voltage to the internal heating element of the reductant pump assembly when the reductant temperature approaches 12°F (-11°C)….

P208E – Reductant Injector Valve Stuck Closed, Bank 1, Unit 1

Meaning of Code P208E

Code P208E indicates a malfunction in the reductant injection valve circuit (also called the SCR dosing valve). This component plays a crucial role in:
✅ Precise dosing of the reductant (AdBlue) before its injection into the exhaust gases.
✅ Liquid atomization for an optimal reaction with NOx in the SCR catalyst.
✅ System cooling via heat-dissipating fins.

If the valve does not function correctly, the SCR system may deactivate, leading to an increase in polluting emissions and a risk of damage to the catalyst.

Possible Causes of Code P208E

Several elements can trigger this fault:

1. Reductant Injection Valve Failure

Obstruction or fouling (AdBlue crystallization).
Internal electrical failure (defective coil or circuit).
Overheating (poor cooling of the heat-dissipating fins).

2. Electrical Problems

Cut or short-circuited wiring harness to the valve.
Oxidized, loose, or damaged connectors.
Ground or power supply voltage issue.

3. PCM/SCR Module Failure

Programming error or software malfunction.
Poor control of injection frequency (normally between 0.3 Hz and 3 Hz).

Symptoms of Code P208E

🚨 Check engine light on (and possibly a “Anti-pollution system fault” message).
⚠ Increased NOx emissions (risk of failing technical inspection).
⛽ Decreased engine performance (possible limp mode).
💧 Leak or ammonia odor (if AdBlue is not properly vaporized).

How to Diagnose and Repair Code P208E?

🔧 Necessary Tools:

OBD2 scanner (to check real-time data).
Multimeter (continuity and voltage test).
SCR injector cleaner (if fouled).

📋 Diagnostic Steps:

1. Visual Inspection

Check the condition of the wiring harness and connectors (look for cut wires, corrosion).
Inspect the cooling fins (dust off if necessary).

2. Electrical Test of the Valve

Measure the coil resistance (check manufacturer specifications).
Test power supply and ground with the engine running.

3. Cleaning or Replacement

If the valve is fouled, use a special AdBlue cleaner.
If defective, replace it with an original part.

4. SCR/PCM Module Verification

If the problem persists, reprogramming or replacing the module may be necessary.

Conclusion

Code P208E signals a critical problem in the SCR system, which can lead to excessive pollution and loss of performance. A quick check of the injection valve, wiring, and control module is essential.

⚠ Ignoring this code can damage the catalyst and increase repair costs!

🔧 Need help? Consult an SCR specialist for an accurate diagnosis.

➡ Is your vehicle displaying this code? Describe your symptoms in the comments for personalized advice!