B0991 Trouble Code

View B0991 obd/2 error code description and symptoms. B0991 engine photo

Throttle Position (TP) Sensor Intermittent The TP sensor circuit is monitored by the PCM for sudden TP rotation angle (or voltage) input change through the comprehensive component monitor (CCM). If during the last 80 warm-up cycles in key ON engine running the PCM detects a TP rotation angle (or voltage) changes beyond the minimum or maximum calibrated limit, a continuous diagnostic trouble code (DTC) is stored. Poor continuity through the TP sensor connectors Poor continuity through the TP harness Intermittent open or short inside the TP sensor While accessing the TP V PID on the scan tool, lightly tap on the TP sensor or wiggle the TP sensor connector and harness.

A good starting point in your diagnosis is checking all system fuses and fusible links. This can be done using the DVOM on the voltage setting. You will want to test the fuses with circuits loaded. Some fuses will appear normal until a load is placed on their respective circuit; at which point they will fail. This has been the cause of many 'phantom malfunctions'. Consult your vehicle information source for fuse and fusible link locations. If all fuses are in working order, you may want to check TCM relay operation by swapping identical relays. Usually the horn relay, starter relay, fuel pump relay, air conditioning clutch relay, and controller relays are similar enough in design to swap for diagnostic purposes.

B0991 Error Code Repair Process :

If your transmission neutral safety switch short circuit to battery check engine light is illuminated, it's best to take it in for diagnostic testing, which can feel like a hassle. Because while the lights vary in appearance from vehicle to vehicle, all have the same basic meaning: There's a problem with the car's emissions system. The on-board diagnostics system B0991 and engine control unit are in charge of monitoring a bunch of different transmission neutral safety switch short circuit to battery, and if they get a reading that's a little out of whack, up pops the check engine light.

Common Causes of B0991

A common cause of code B0991 is the failure of Transmission Neutral Safety Switch Short Circuit To Battery, but there are several other possible causes as well, such as ;

Damaged VCT phaser
Faulty Fuel injector
Incorrect fuel pressure
Variable Camshaft Timing (VCT) position circuit is open or shorted

B0991 Trouble Code

B0991 Error Code Repair Process :

Common Causes of B0991

B0991 code for all cars