DTC 31

Code 31:

Code 31:

CIRCUIT DESCRIPTION:

The Manifold Absolute Pressure (MAP) Sensor responds to changes in manifold pressure (vacuum). The ECM receives this information as a signal voltage that will vary from about 1 to 1.5 volts at closed throttle idle, to 4-4.5 volts at wide open throttle. If the MAP Sensor fails, the ECM will substitute a fixed MAP value and use the Throttle Position Sensor (TPS) to control fuel delivery.

TEST DESCRIPTION: Numbers below refer to circled numbers on the diagnostic chart.

1. This step verifies that 5V reference is available from the ECM.

2. This step verifies the ECM is grounding the circuit.

DIAGNOSTIC AIDS:

An intermittent may be caused by a poor connection rubbed through wire insulation or a wire broken inside the insulation. Inspect ECM harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, poor terminal to wire connection and damaged harness.