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P1790

Symptom: No downshifting for fast acceleration

P1790

Kick-down switch, shorted to ground.

Fault symptom

No downshifting for fast acceleration

Condition

Shorting to ground at the same time as the throttle position is less than 70%% for at least 2 seconds.

Diagnostic help

A reading of the kickdown switch status can be obtained with the diagnostics instrument. Select "READ ON/OFF". Select "KICKDOWN SWITCH". With the accelerator fully depressed, i.e. in the kickdown position, the diagnostics instrument will show ON, otherwise OFF.

Diagnostic procedure

1 Check the transmission control module's signal input






- Unplug the kick-down switch connector.

- Connect the Scan tool diagnostics instrument.

- Turn the ignition switch to the ON position.

- Select "READ ON/OFF".

- Select ""KICKDOWN SWITCH".


Read the diagnostics instrument with


connector pin 1 open "OFF"

connector pin 1 connected to a good grounding point "ON"


Is the diagnostics instrument reading correct?

yes

Continue with point 3.


no

Rectify the lead (including connector) between the kickdown switch connector pin 1 and the control module pin 8 and continue with step 2.


2 Check the kick-down switch's connection to ground





- Turn the ignition switch to the ON position.

- Connect a test lamp to pins 1 and 2 of the connector. The lamp should light up.


Did the test lamp light up?

yes

Adjust or, if necessary, replace the kick-down switch and continue with point 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 the diagnostic trouble code, drive the car on test at varying engine loads and speeds for 5 minutes and obtain readouts of any diagnostic trouble codes that are generated.

Does the diagnostic trouble code recur?

yes

Continue with .


no

The remedial action taken was correct.