P1231

P1231

Throttle Position Sensor 1 and 2 Circuit. Sum Out of Range (No Limp Home).
Brief disturbances in the throttle valve control which causes the engine to surge.







Preliminary information
- The DTC is to be disregarded if it is generated together with other throttle bodyrelated DTCs.

Purpose
The purpose of this DTC is to report if sporadic surging occurred at constant speed and/or if idling is uneven. The surge can occur relatively seldom and feel like driving over minor unevenness in the road. In the worst cases, the surge may seem like rapid, brief loss of engine power, which can generate suspicion that the ignition discharge module is faulty.

NOTE: The surge must not be confused with the surges that can occur when the engine is heavily loaded.

Technical explanation
The cause of the problems is one of the potentiometers (pot.1) in the throttle body. The throttle will then make brief movements in the closing direction. In this case, irregular idling may be noticeable or there may be surging when driving on motorways. The fault is not significant from a safety standpoint and does not affect exhaust emission control.

Procedure
Discuss with the customer how often and how long the symptom has appeared and if it requires replacement of the throttle body.

On-board diagnosis

Type of diagnosis:
- Continuous.

Enable criteria:
- Engine speed up to 4000 rpm.
- Even acceleration.

The number of surges is registered and stored in the engine management system and will finally lead to the DTC.

Fault criteria:
- The engine management system has on several instances registered that the throttle valve does not follow the control module's requested control

Dependencies:
- None.

System reactions to fault:
- None.

OK report:
- The DTC disappears when there are no surges for a longer period of time.

Fault handling: (For more information, Fault Handling III, Other Emission-Related Components and Function)

- Type III.