Diagnostic Aids

An intermittent may be caused by the following:

• Poor connections.
• Misrouted harness.
• Rubbed through wire insulation.
• Broken wire inside the insulation.

Check for the following conditions:

• MAP sensor shares a 5-volt reference with the Fuel Tank Pressure, APS1, APS3, and EGR valve.
• MAP sensor shares a ground with the Fuel Tank Pressure, the ECT sensor and the Transmission Fluid.
• Poor connection at PCM: inspect harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, and poor terminal to wire connection.
• Damaged harness: inspect the wiring harness for damage. If the harness appears to be okay, observe the APP sensor 1 display on the TECH 2 while moving connectors and wiring harnesses related to the sensor.

A change in the display will indicate the location of the fault. If DTC P1275 cannot be duplicated, the information included in the Failure Records data can be useful in determined vehicle mileage since the DTC was last set. If it is determined that the DTC occurs intermittently, performing the DTC P1275 diagnostic procedures may isolate the cause of the fault.