Throttle Control: Diagnostics
- Diagnostic trouble code P1230 is generated if one of the throttle position sensors is faulty. The software is being successively change during MY02 to make fault diagnosis less sensitive to normal disturbances. It is therefore important not to change the throttle body if the control module is running the old software.
- Diagnostic trouble code P1231 can be generated by a very brief break in a throttle position sensor circuit, caused by the dirt normally found on the potentiometer.
- Diagnostic trouble codes P1240 , P1251 -P1253 , P1260 -P1261, P1263 or P1264 are generated if there is a throttle motor malfunction or a mechanical fault.
- Diagnostic trouble codes P1601-P1611, P1613-P1614 or P1621 are generated if an internal fault should occur in the control module that affects the throttle control.
- Diagnostic trouble codes P1670-P1671 are generated if there is an open circuit or short circuit on the control module output to the relay for the limp-home solenoid.
Most of the above faults will put the throttle control into limp-home mode.
IMPORTANT:
When the throttle control system is in limp-home mode, the fault is stored in the control module memory. Each time the ignition is switched on, the limp-home solenoid is activated for 1 s and then for 4 x 0.5 s to ensure that the mechanism is not reset before the fault has been rectified. Repair work must therefore be carried out in the following order:
Silicone sprays must not be used on the electrical or mechanical parts of the throttle body.
- Rectify the fault.
- Delete the DTCs.
- Reset the limp-home mechanism.
If this sequence is not followed, it is highly likely that the car will leave the workshop with the throttle control system still in limp-home mode. When the system detects that it is in mechanical limp-home mode, diagnostic trouble code P1260 , P1263 or P1251 will be generated.
Silicone sprays must not be used on the electrical or mechanical parts of the throttle body.
The throttle body must not be washed.