To return temperature data to the ECU, the hydraulic oil temperature sensor uses an electrical signal that returns to the engine computer through a series of wires and connectors. If an abnormally low voltage signal is detected on the hydraulic oil temperature sensor circuit, a DTC P0939 will be recorded.

How severe is the code?

Diagnostic trouble code P0939 is very serious, as it means the ECU may not be able to prevent overheating and severe internal damage without reliable hydraulic oil temperature data.

Symptoms

Symptoms of a P0939 include:

• Check engine light
• Overheating
• Erratic vehicle behavior
• Limp mode

Causes

• Corroded/broken connectors
• Damaged wiring
• Faulty hydraulic oil temperature sensor
• Hydraulic fluid level too low
• Dirty hydraulic fluid

How to diagnose the code?

The diagnostic process for OBDII trouble code P0939 should begin with checking the level and condition of the hydraulic oil itself (if dirty, change it). The wiring and connectors along the circuit should also be carefully inspected for signs of damage on wires and corroded or broken connectors. If no issues are detected, the hydraulic oil temperature sensor will need to be tested. The ECU itself may also need to be reprogrammed or replaced.

What repairs will fix P0939?

• Repair damaged wiring and/or connectors
• Replace the hydraulic oil temperature sensor
• Change the hydraulic fluid
• Reprogram or replace the ECU

P093A, P093B, P093C, P093D, P093E, P093F ISO/SAE Reserved

The hydraulic oil temperature is closely monitored by the ECU, allowing it to make adjustments on the fly to prevent overheating. If there is an abnormally high voltage signal in the hydraulic oil temperature sensor circuit, this temperature data will be compromised and a DTC P0940 will be triggered.

How severe is the code?

The diagnostic code P0940 is quite serious, as it means the ECU does not know the current temperature of the hydraulic oil. This can obviously lead to overheating, which may result in severe/expensive damage.

Symptoms

Symptoms of a P0940 include:

• Check engine light
• Overheating
• Irregular vehicle behavior
• Limp mode

Causes

• Damaged/corroded wiring and/or connectors
• Faulty hydraulic oil temperature sensor
• Low hydraulic fluid
• Dirty hydraulic fluid/filter

How to diagnose the code?

Diagnosing an OBDII fault code P0940 should start with checking the condition of the hydraulic oil (if it is dirty, it will need to be changed). The wiring and connectors along the hydraulic oil temperature sensor circuit should then be closely inspected for signs of damaged wires and corroded or broken connectors. The sensor itself may also need to be tested, possibly along with the ECU.

What repairs will fix P0940?

• Repair damaged wiring and/or connectors
• Replace the hydraulic oil temperature sensor
• Change the hydraulic fluid
• Reprogram or replace the ECU

To prevent overheating and the costly damage that accompanies it, the ECU relies on sensors like the hydraulic oil temperature sensor. It sends electrical pulses to the computer with constantly updated temperature data. If this signal suddenly becomes intermittent, a DTC P0941 will be triggered.

How serious is the code?

The diagnostic code P0941 is very serious, as it means the hydraulic oil/transmission fluid temperature is no longer being constantly monitored. This leads to a number of driving problems, as well as the possibility of very serious damage.

Symptoms

Symptoms of a P0941 include:

• Check engine light
• Overheating
• Irregular vehicle behavior
• Limp mode

Causes

• Damaged wiring and/or connectors
• Faulty hydraulic oil temperature sensor
• Dirty or low hydraulic fluid

How to diagnose the code?

The first thing to do when trying to diagnose a P0941 OBDII fault code is to check the level and condition of the hydraulic fluid (it should be changed if it is excessively dirty or if there are metal fragments). Then, the condition of the wiring and connectors along the hydraulic oil temperature sensor circuit should be checked for signs of damage and corrosion. The sensor itself may need to be tested, as well as the ECU.

What repairs will fix P0941?

• Repair damaged wiring and/or connectors
• Replace the hydraulic oil temperature sensor
• Change the hydraulic fluid
• Reprogram or replace the ECU

The P0942 DTC is commonly found in vehicles manufactured by Chrysler Corporation or Volkswagen. However, a few other car manufacturers are known to use it. What this OBDII fault code means is that there is a significant issue with the transmission pump that creates the hydraulic pressure needed to operate the transmission, and ultimately the drive wheels.

How severe is the code?

The P0942 diagnostic code is actually quite serious, as the transmission must have the correct hydraulic pressure to function properly. If it doesn’t, you could be facing a massive repair bill.

Symptoms

Symptoms of a P0942 include:

• Delayed shifts
• The transmission refuses to shift

Causes

• Low or dirty transmission fluid
• Blocked or loose transmission cooler lines/filter
• Faulty transmission pump
• Fluid blockage inside the transmission body/valve
• The transmission pressure regulator valve is stuck

How to diagnose the code?

Diagnosing a P0942 OBDII fault code typically involves performing a transmission line pressure test to see if the transmission pump is working correctly. Transmission leaks will need to be fixed, and the condition of the transmission fluid should be checked for signs of internal damage.

What repairs will fix P0942?

• Change the transmission fluid
• Flush the transmission
• Replace the cooling line filter
• Replace the transmission pump
• Replace the transmission regulator valve
• Replace, rebuild, or install a remanufactured transmission

This OBD2 code is commonly used on Chrysler Corp. and VW vehicles, and it concerns the transmission pump. If the ECU detects that it is not operating according to preprogrammed parameters, it will trigger a DTC P0943.

How severe is the code?

A P0943 diagnostic code is extremely severe, as it means the transmission pump is not producing enough hydraulic pressure to operate the transmission safely. This can lead to catastrophic damage to the transmission, so it must be diagnosed immediately.

Symptoms

Symptoms of a P0943 include:

• Delayed gear shifts
• The transmission refuses to shift gears

Causes

• Low transmission fluid level
• Dirty fluid/filter
• Blocked or loose transmission cooler lines/filter
• Transmission pump failure
• One of the fluid passages inside the transmission body/valve is obstructed
• Non-functional transmission pressure regulator valve

How to diagnose the code?

The diagnostic process for an OBDII P0943 fault code involves performing a transmission line pressure test to determine if the transmission pump is functioning correctly. If it is not, it will need to be replaced.

What repairs will fix P0943?

• Change the transmission fluid
• Flush the transmission
• Replace the cooling line filter
• Replace the transmission pump
• Replace the transmission regulator valve
• Replace, rebuild, or install a remanufactured transmission

The P0944 DTC is often used on VW and Chrysler Corp. vehicles when the transmission pump stops producing hydraulic pressure. This is a serious OBD2 code and must be addressed immediately.

How severe is the code?

The P0944 diagnostic code is actually one of the most serious OBDII transmission diagnostic codes you can have. If the transmission loses hydraulic pressure, it will literally not be able to function. When this happens, serious internal damage occurs.

Symptoms

Symptoms of a P0944 include:

• Delayed shifts
• The transmission refuses to shift

Causes

• Dirty or low transmission fluid
• Blocked or loose transmission cooler lines/filter
• Faulty transmission pump
• Internal hydraulic passage blockage
• Stuck transmission pressure regulator valve

How to diagnose the code?

The best way to diagnose a P0944 OBDII trouble code is to perform a transmission line pressure test. This will tell the technician whether or not the transmission pump is creating sufficient hydraulic pressure.

What repairs will fix P0944?

• Change the transmission fluid
• Flush the transmission
• Replace the cooler line filter
• Replace the transmission pump
• Replace the transmission regulator valve
• Replace, rebuild, or install a remanufactured transmission

DTC P0945 is triggered when the ECU detects an electrical problem in the hydraulic pump relay circuit. Often referred to as the transmission pump, it is one of the most important transmission components in your gearbox. Therefore, this OBDII fault code must be diagnosed immediately.

How severe is the code?

Diagnostic code P0945 is extremely severe because the transmission pump creates the hydraulic pressure that turns your wheels. If there is a problem with the transmission pump relay, you may experience a number of driving issues while causing significant or catastrophic transmission damage.

Symptoms

Symptoms of a P0945 include:

• Unusually harsh shifts
• Transmission slipping between gears
• Failed gear change

Causes

• Low or dirty transmission fluid
• Damaged wiring or connectors
• Faulty hydraulic pump relay
• ECU or TCM issues

How to diagnose the code?

The first step in diagnosing an OBDII fault code P0945 is to check the transmission fluid level and condition. Then, the technician should look for any damaged wiring or corroded connectors between the relay panel and the transmission. The hydraulic pump relay/transmission pump relay will also need to be tested.

What repairs will fix P0945?

• Change the transmission fluid/filter
• Repair or replace damaged wiring and/or connectors
• Replace the hydraulic pump relay
• Reprogram or replace the ECU/TCM

The transmission pump is responsible for converting the rotational force generated by the engine into hydraulic pressure that activates the transmission and turns the drive wheels of your vehicle. If the hydraulic pump relay circuit does not operate according to the predefined parameters programmed in the ECU, a DTC P0946 will be recorded.

How severe is the code?

A diagnostic code P0946 means that the hydraulic pump relay/transmission pump relay may not be functioning correctly, which could impact the performance of the transmission pump itself. This could lead to a number of driving issues, as well as serious/expensive damage.

Symptoms

Symptoms of a P0946 include:

• Generally harsh gear shifts
• Slipping between gears
• The transmission will not shift gears

Causes

• Dirty fluid/filter
• Low transmission fluid level
• Damaged wiring and/or connectors
• Faulty hydraulic pump relay
• ECU or TCM issues

How to diagnose the code?

When diagnosing an OBDII fault code P0946, the hydraulic pump relay must be tested to ensure it is functioning. If it is, the transmission fluid level and condition should be checked. The wiring and connectors between the relay panel and the transmission panel should also be inspected for signs of damage and corrosion.

What repairs will fix P0946?

• Change the transmission fluid/filter
• Repair or replace damaged wiring and/or connectors
• Replace the hydraulic pump relay
• Reprogram or replace the ECU/TCM

Definition of Code P0947

Code P0947 is a generic powertrain code related to the transmission, including pressure faults and sensor failures. In this case, the transmission control module detected a low voltage signal from the hydraulic pump relay circuit.

What Does Code P0947 Mean?

A vehicle uses the pump to generate hydraulic pressure. The channels direct transmission fluid in an automatic transmission to the valve body. Both the shift solenoids and the pressure control solenoids are located in the valve body. The transmission control module manages and activates the electronically controlled valves, which are used for shifting. Specifically, the shift solenoid controls the transmission’s clutch, brakes, and bands, while the pressure control solenoid (one or more) manages the hydraulic pressure inside the vehicle’s transmission.

A code P0947 will be recorded when the transmission control valve receives a voltage signal lower than the manufacturer-specific allowable variations from one of the valves.

What Causes Code P0947?

Several issues can cause a code P0947, including:

• Low transmission fluid
• Dirty transmission fluid
• Damaged or faulty wiring or associated electrical connector
• Damaged or faulty hydraulic pump relay
• Damaged or faulty transmission control module
• Damaged or faulty ECM

What Are the Symptoms of Code P0947?

Symptoms of a code P0947 may include:

• Check engine or warning light may illuminate
• Vehicle may shift roughly
• Vehicle may not move at all
• May exhibit transmission slipping

How Does a Mechanic Diagnose Code P0947?

A mechanic may use several methods to diagnose a P0947 fault code, including:

• Using an OBD-II scanner to check for a stored P0947 fault code
• Checking transmission fluid levels
• Checking transmission fluid quality
• Checking the transmission pan for any debris, including clutch debris, which could indicate a larger transmission-related issue
• Visually inspecting wiring and electrical components related to the hydraulic pump relay circuit for possible damage
• Specifically checking the transmission control module harness to the transmission for any signs of damage
• Checking resistance between terminals
• Repeating the resistance test at the transmission connector if resistance is not at normal levels

Common Mistakes When Diagnosing Code P0947

With any transmission-related error code, it is recommended to check transmission fluid levels and quality, test the vehicle, and reanalyze to see if the code reappears before performing more complicated diagnostics and repairs.

How Severe Is Code P0947?

Since safely operating a vehicle will most likely be affected due to faults that store a P0947 code, this code is considered potentially severe. 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 P0947?

Several repairs can correct a P0947 fault code and include:

1. Fill transmission fluid to manufacturer-recommended levels
2. Change or perform a transmission fluid flush, if necessary
3. Repair or replace damaged, open, shorted, or corroded wiring and electrical components related to the hydraulic pump relay circuit
4. Replace the damaged or faulty transmission control module harness to the transmission
5. Replace the damaged or faulty hydraulic pump
6. Replace the damaged or faulty transmission control module
7. Replace the damaged or faulty ECM
8. Clear all codes, test the vehicle, and reanalyze to see if any codes reappear