P1813

DIAGNOSTIC TROUBLE CODES P1812 AND P1813
TRANSMISSION FLUID TEMPERATURE SENSOR, INPUT TO TCM TOO LOW/SHORT CIRCUIT TO GROUND (P1812)
INPUT TO TCM TOO HIGH/OPEN CIRCUIT OR SHORT CIRCUIT TO BATTERY POSITIVE VOLTAGE (P1813)

Fault symptom
Disturbances in lock-up function and gear shifting function at higher temperatures.

Conditions.
P1812: Short circuit to ground.
P1813: Short circuit to battery voltage or an open circuit and if the Transmission Control Module (TCM) reads an transmission fluid temperature less than -10°C after the engine has been running for about 5 minutes.

Diagnostic procedure
1. Connect ISAT scan tool to the car's data link connector. Check the transmission fluid temperature by initiating FLUID TEMPERATURE in ISAT menu READ FUNCTIONS and read the value. Ignition should be switched ON. With a warm engine and transmission the nominal value is about 80°C and about 1.1 V.

If the measurement result is correct, go to step 9.

If the measurement value is wrong, go to step 2.





2. With the ignition switched OFF, disconnect connector H10-1 located behind the battery in the engine compartment (black 10-pin Packard connector).

Connect an ohm meter between pins 5 and 6 in the connector whose wiring goes to the transmission (H10-1 female). Nominal resistance is as specified in the table below:





If the measurement result is correct, go to step 6.

If the measurement value is wrong, go to step 3.

3. With the ignition switched OFF, disconnect the connector to the transmission fluid temperature sensor, 535, on the transmission (black 2-pin Packard connector).

Connect an ohm meter between pins 1 and 2 in the connector whose wiring goes to the transmission (male). Nominal resistance is as stated in step 2.

If the measurement result is correct, go to step 4.

If the measurement value is wrong, check the connector and the wiring to the transmission fluid temperature sensor and remedy any faults. If you find any fault which cannot be remedied, install a new temperature sensor.





4. With the ignition switched OFF, carry out continuity measuring of the wiring between connector H10-1 pin 5 (female) and connector 535 pin 1 (female) and connector H10-1 pin 6 (female) and connector 535 pin 2 (female). Connect an ohm meter as described above. Nominal resistance is <1 ohm.

If the ohm meter shows the correct value, go to step 5.

If the ohm meter shows a different value, check the connectors and the wiring between them and remedy any faults.

5. Check connector H10-1 for slide-outs and remedy any faults.

Go to step 9.

6. With the ignition switched OFF, connect a BOB between TCM and wiring.

Carry out continuity measuring between pin 33 and connector H10-1 pin 5 (male). Nominal resistance is <1 ohm.

If the measurement result is correct, go to step 8.

If the measurement result is wrong, check the wiring between them and remedy any faults.

7. Carry out voltage measuring in pin 33. Reference ground is pin 35. Nominal voltage is 1.1 V.

If the measurement result is correct, go to step 8.

If the measurement result is wrong, go to "Actions Before Changing a TCM".





8. Check the transmission fluid temperature by initiating FLUID TEMPERATURE in ISAT menu READ FUNCTIONS and read the value. The ignition should be switched ON. With a warm engine and transmission the nominal value is about 80°C and 1.1 V.

If the measurement result is correct, go to point 9.

If the measurement result is wrong, go to "Actions Before Changing a TCM".

9. Clear the diagnostic trouble code, start and test drive the car and check if the fault code reappears.

If a diagnostic trouble code is recorded, go to "Actions Before Changing a TCM".