Diagnostic Aids

If a TP sensor No. 1 or No. 2 DTC is set, diagnose that DTCs first.

If DTC P1511 is set, the ECM will default to one of the two limp home modes (random injector disable with engine speed limited to 1800 RPM). The REDUCED POWER telltale will be illuminated and the ECM will remain in this condition for the entire ignition cycle even if the fault is corrected.

Possible causes of DTC P1511:

• Weak throttle body return springs or throttle plate sticking.
• TP sensor No. 1 or No. 2 skewed or resistance in the wiring.