The throttle control module contains a throttle control motor, two throttle
position (TP) sensors, and two independent signal circuits that vary resistance according
to changes in throttle plate position. The ECM will go through a throttle position
learn in procedure to determine acceptable values for the throttle plate position
operating range. This is based on the inputs from TP sensor 1 and TP sensor 2 and
feedback from the throttle control motor. DTC P1511 sets if the ECM is in REDUCED
PERFORMANCE mode and the throttle position falls outside a calibrated range.
DTC PARAMETERS
DTC P1511 sets if the ECM is in REDUCED PERFORMANCE mode and the throttle position
falls outside a 3.7 - 9.8% range when:
| • | Vehicle speed is not present |
| • | Engine speed less than 2500 rpm |
| • | ECT between 5°C - 100°C (41°F - 212°) |
| • | IAT greater than 5°C (41°F) |
| • | Battery voltage greater than 10 volts |
| • | Pedal position less than 15% |
DTC P1511 diagnostic runs continuously when the above conditions are met.
P1511 is a (type A) DTC
DIAGNOSTIC AIDS
This DTC P1510 may set due to either mechanical faults or electrical circuit
faults. Possible causes:
| • | Weakened springs in throttle assembly |
| • | Throttle plate forced to extreme position due to a surge of air or carbon
deposits |
| • | Circuit failure to throttle control motor |
| • | TP sensor not functioning properly (diagnose TP sensor DTCs first) |
If DTC P1511 is set, the ECM detected a fault with the backup throttle control
system in REDUCED PERFORMANCE mode. If the condition is a hard fault, the engine
will not restart once the ignition is cycled Off.
