P1790

P1790
Kickdown switch, short circuit to ground

Fault symptoms
No downshifting when accelerating quickly.

Conditions
Short circuit to ground while throttle position is less than 70% for at least 2 seconds.

Diagnostic help
The state of the kickdown switch can be read with the diagnostics tool.
Select "Read Values."
Select "Kickdown switch."
With the accelerator pedal fully depressed, i.e. kickdown, ON will be displayed, otherwise OFF.






Diagnostic procedure

1 Check the control module signal input
- Unplug the kickdown switch connector.
- Connect a diagnostic tool.
- Turn the ignition to the ON position.
- Select "Read Values."
- Select "kickdown switch."
Read the diagnostic tool with
- connector pin 1 open "OFF"
- connector pin 1 connected to a good grounding point

Are the diagnostic tool readings correct?
YES
Continue with step 3.
NO
Rectify the lead (including connector) between the kick-down switch connector pin 1 and the control module pin 8 and continue with step 2.






2 Check the kickdown switch ground connection
- Turn the ignition to the ON position.
- Connect a test lamp between connector pins 1 and 2. The lamp should light up.

Is the lamp alight?
YES
Adjust or, if necessary, replace the kickdown switch and continue with step 3.
NO
Rectify the lead (including connector) between the kickdown switch connector pin 2 and grounding point G4, and continue with step 3.






3 Final check
- Clear all diagnostic trouble codes in the system.
- Perform a driving cycle:
- Drive the car at varying loads and engine speeds for 5 minutes.
- Evaluate the driving cycle:
- Make sure the trouble code has not recurred.

Has the trouble code recurred?
YES
Continue with "Before changing a control module," see Fault diagnosis, general, "Before changing a control module." Before Changing A Control Module

NO
The steps taken to rectify the fault were correct.