E032

TEST CONDITIONS
Code EO32 is tested under two separate conditions:
A.
1. RPM less than or equal to 700;
2. TPS less than or equal to 18 degrees;
3. Throttle switch closed
B.
1. RPM less than or equal to 1800;
2. TPS equal to or greater than 13 degrees;
3. Throttle switch open.
4. Not in P/N.

FAILURE CONDITIONS
MAP value less than or equal to 15 kPa for 0.1 seconds.

ACTION TAKEN
1. ECM turns on "Engine Control System Fault" telltale;
2. ECM commands BCM to display "Service Now" message on Driver Information Center (DIC);
3. AIR directed to the air cleaner;
4. ECM set BARO to 92 kPa;
5. ECM uses a substitute MAP value based on engine RPM and throttle switch status (open or closed).

DESCRIPTION
The manifold absolute pressure sensor (MAP) is a "3-wire" sensor, a potentiometer that change resistance based upon manifold vacuum. The ECM provides a 5 volt reference on CKT 474 and ground on CKT 476. The MAP signal (CKT 432) varies between ground and 5 volts as manifold vacuum varies. As MAP decreases, voltage decreases (low engine load, high vacuum). As MAP increases, voltage increases (high engine load, low vacuum).

The ECM uses MAP sensor values as an indicator of engine load. A high MAP reading indicates heavy load and a low MAP reading indicates a light load.
Code EO32 sets when the ECM detects a MAP sensor signal too low (MAP value less than or equal to 15 kPa).

Possible causes of Code EO32 are
1. Short to ground on CKT 432;
2. Defective MAP sensor.
3. Loss of 5V to MAP sensor.

Notes on Fault Tree
1. Checking for circuitry from sensor to ECM able to respond to a 5 volt signal on MAP input. A reading of 106-109 means wiring and ECM are OK.
2. Checking for 5 volt reference present at sensor connector.
3. Checking for CKT 432 shorted to ground.
4. Checking for ECM able to respond to a 5 volt signal voltage on MAP input.
5. Fault is most likely at ECM connector or ECM. Before ECM is replaced, perform "ECM Replacement Check", Chart C- 1. Chart C-1 Vehicle Will Not Enter Diagnostics

Notes on Intermittents
Manipulate MAP sensor connector, MAP wiring, and ECM connector while observing ECM data ED02. Apply and release vacuum to the MAP sensor vacuum port using a vacuum source. If the ECM data ED02 immediately jumps to less than 15 kPa, repair intermittent MAP sensor fault. If wiring and connector check out ok, substitute a known good MAP sensor and retest.