Powertrain Controls - ECM/PCM

DTC 32 Chart:

CIRCUIT DESCRIPTION
The Manifold Absolute Pressure (MAP) sensor responds to changes in manifold vacuum. The PCM provides the MAP sensor with a 5 volt reference and a sensor ground. The MAP sensor varies the signal on CKT 432 to PCM between 0 and 5 volts depending on manifold vacuum. As vacuum increases, the MAP signal voltage will decrease indicating low engine load. As vacuum decreases, the MAP signal voltage will increase indicating higher engine load. If the PCM detects the MAP sensor signal voltage less than 1.0 volt, DTC 32 will set.

DTC 32 WILL SET WHEN
- Engine RPM is less than 700 RPM and Throttle Position (TP) is less than 18 degrees throttle angle.
- MAP signal indicates less than 0.08 volts (8.5 kPa).
OR
- Transmission is not in park or neutral position.
- Engine RPM is less than 1800 RPM and Throttle Position (TP) is greater than 13 degrees throttle angle.
- MAP signal indicate than 0.08 volts (8.5 kPa)

ACTION TAKEN (PCM WILL DEFAULT TO)
- With a current DTC 32 set, the PCM will illuminate the Malfunction Indicator Lamp (MIL) (Service Engine Soon).
- The PCM will disable the long term fuel correction and substitute a default MAP value based on engine RPM and throttle position switch status.

DTC 32 WILL CLEAR WHEN
The fault no longer exists.

DTC CHART TEST DESCRIPTION
Number(s) below refer to circled number(s) on the diagnostic chart.

1. If MAP sensor or circuitry are open, Tech 1 will read 10-16 kPa.
2. Checking if circuitry from sensor to PCM is able to respond to a 5 volt signal on MAP input. A reading of 103-105 means wiring and PCM are OK.
3. Checking for a short to ground on CKT 432 or an open in CKT 432, CKT 474 or in the MAP sensor.
4. Checking for CKT 432 shorted to ground.
5. Checking if 5 volt signal is reaching the PCM. If signal is present, replace PCM.

DIAGNOSTIC AIDS
An intermittent open in CKT 432 or CKT 416 will result in a DTC 32.
With the ignition "ON" and engine stopped, the manifold pressure is equal to atmospheric pressure and the signal voltage will be high. This information is used by the PCM as an indication of vehicle altitude. Comparison of this reading with a known good vehicle with the same sensor is a good way to check accuracy of a "suspect" sensor. Readings should be the same ±0.4 volt.