Throttle Control: Diagnostics

2002 Saab 9-3 SE, 2D Convertible, AutomaticSECTION Diagnostics
Fig 1: Diagnosing Throttle Position Sensor
G03576959Courtesy of SAAB-SCANIA OF AMERICA, INC.
  • 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:
  1. Rectify the fault.
  2. Delete the DTCs.
  3. 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.

RENDER: 1.0x

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • You smell fuel, burning insulation, or see smoke.
  • Brakes feel soft, pull hard to one side, or make grinding noises.
  • The engine overheats, stalls repeatedly, or misfires under load.
  • You are missing required tools, torque specs, or safe lifting equipment.
  • You are not confident in the next step or safety outcome.