P1842

DIAGNOSTIC TROUBLE CODE P1842
SIGN. TORQUE LIMITATION, TO FUEL SYSTEM OUTPUT SIGNAL LOW/OPEN CIRCUIT OR SHORT CIRCUIT TO GROUND

Fault symptom
Warning lamp CHECK ENGINE lit. The system's emergency program is activated. The loss of the signal for torque limitation results in hard gear shifting.

Condition
Short circuit to ground or open circuit.

Diagnostic procedure
1. Connect ISAT scan tool to the car's data link connector. Check the torque limitation by initiating TORQUE LIMIT in ISAT menu ACTIVATE.

If the function works, go to step 5.

If the function does not work, go to step 2.

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

2. Carry out continuity measuring of the wiring between the Transmission Control Module (TCM) and the ECM.

With the ignition switched OFF, connect one BOB between the TCM and the wiring and another BOB between the ECM and the wiring.

Connect an ohm meter between the TCM pin 13 and the ECM's pin 51. Normal resistance is <1 ohm.

If the ohm meter shows the correct value, go to step 6.

If the ohm meter shows a different value, go to step 3.





3. Check wiring and connectors between the TCM and the engine control system's ECM. Connector H33-4 is situated behind the glove compartment.Carry out continuity measuring of the wiring by means of ohm measuring.

Connect an ohm meter between:
- the TCM pin 13 and H33-4 pin 32.
- H33-4 pin 32 and ECM pin 51. Nominal resistance is <1 ohm.

If the ohm meter shows the correct value, go to step 6.

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





4. Initiate TORQUE LIMIT in ISAT menu ACTIVATE and measure the output signal, pin 13 to pin 35, in parallel. Nominal values are 1 Hz (signal changes between 12 V and ground).
Signal is low <250 ms.

If the measurement result is correct, go to fault-tracing in the engine control system.

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

If the function works, go to step 5.

5. Clear the fault code, start and test drive the car and check if the fault code reappears.

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