Section04ENGINEMANAGEMENT(15034-TEC)
Subsection 02 (DIAGNOSTIC PROCEDURES)
TPS (Throttle Position Sensor) Faults
Faults which are reported in B.U.D.S. fall into two groups: TPS faults and adaptation faults. These are
displayed on the B.U.D.S. system as TPS OUT OF RANGE and TPS ADAPTATION FAILURE.
TPS “OUT OF RANGE” Fault
It is caused by the sensor reading going out of its allowable range. This fault can occur during the whole
range of movement of the throttle.
To diagnose this fully, it is recommended to operate the throttle through its full range. It is also recom-
mended to release the throttle quickly as this may also show up a fault that is intermittent.
POSSIBLE CAUSES ACTION
Check if connector is disconnected from TPS.
• Fix.
Check if sensor is loose. • Fix and reset
Closed Throttle and Idle Actuator.
Inspect sensor for damage or corrosion.
• Replace and reset
Closed Throttle and Idle Actuator
.
Inspect wiring (voltage test). • Repair.
• If bad wiring, repair.Inspect wiring and sensor (resistance test).
• If bad TPS, replace and reset
Closed Throttle and Idle
Actuator
.
Test sensor operation (wear test).
• Replace and reset
Closed Throttle and Idle Actuator
.
TPS “ADAPTATION FAILURE” Fault
It is caused by the idle position moving out of an acceptable range.
Following failures can be effected by a TPS “Adaptation Failure”:
– Idle speed is out of range.
– Engine stops, when throttle is released quickly.
– Engine runs inconsistent in low partload or low RPM.
POSSIBLE CAUSES ACTION
Sensor has been replaced and TPS closed position
not reset.
• Reset
Closed Throttle and Idle Actuator
.
Throttle body has been replaced and TPS closed
position not reset.
• Reset
Closed Throttle and Idle Actuator
.
ECM has been replaced and TPS closed posit
ion
not reset.
• Reset
Closed Throttle and Idle Actuator
.
Throttle cable too tight.
• Fix and reset
Closed Throttle and Idle Actuator
.
Sensor is loose.
• Fix and reset
Closed Throttle and Idle Actuator
.
Throttle bracket is loose.
• Fix and reset
Closed Throttle and Idle Actuator
.
Adjustment screw worn or loose.
• Change throttle body.
smr2005-012 83
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