P1790

DIAGNOSTIC TROUBLE CODE P1790
KICK-DOWN SWITCH, INPUT LOW/SHORT CIRCUIT TO GROUND

Fault symptom
Short circuit to ground at the same time as the throttle position is less than 70% for at least 2 seconds.

Condition
No down-shifting takes place during fast accelerations.

Diagnostic procedure
1. Connect ISAT scan tool to the car's data link connector. Check the status of the input signal by initiating KICKDOWN SWITCH in ISAT menu READ ON/OFF and reading the value. With the ignition switched ON, depress the accelerator pedal fully. ISAT should then show ON. When the accelerator pedal is released ISAT should show OFF.

If the measurement result is correct, go to step 5.

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

2. With the ignition switched OFF, carry out resistance measuring on the kick-down connector. Connect an ohm meter between the kick-down switch 534, pins 1 and 2. Nominal resistance is <1 ohm with the accelerator pedal fully depressed and infinite in all other positions.

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

If the measurement result is wrong, install a new kick-down switch.





3. With the ignition switched OFF, connect a BOB between Transmission Control Module (TCM) and wiring.

Connect an ohm meter between pin 8 and the kick-down switch, 534, pin 1. Nominal resistance is <0.5 ohms.

If the ohm meter shows the correct value, go to step 4.

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

4. Connect a voltmeter to pin 8. Reference point is pin 35. Nominal value is 0 V with the accelerator pedal fully depressed and 12 V in all other positions.

If the voltmeter shows the correct value, go to step 5.

If the voltmeter shows a different value, go to "Actions Before Changing a TCM".

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".