P034

Circuit Description

This diagnostic test monitors the MAP signal for loss of engine vacuum under closed throttle conditions. If the difference between MAP signal and the calculated BARO is 11 kPa or less for 15 seconds, Code P034 sets.

Test Condition(s)

1. Codes P021, P022, P026, P027, P031, P032, not set.
2. Throttle position switch closed.
3. TP sensor 18 degrees or less.
4. RPM 400 or greater.
5. BARO 75 kPa or greater.

Failure Condition(s)

Difference between MAP and Calculated BARO is 11 kpa or less for 15 seconds.

Action Taken

1. PCM turns 'ON' the 'SERVICE ENGINE SOON' MIL.
2. PCM disables long term fuel trim.
3. PCM uses a substitute MAP value based on engine RPM and throttle position switch status.
4. PCM disables Evaporative Emission (EVAP) control solenoid.
5. PCM disables torque management.
6. Transaxle shift adapts are maintained at current levels.

Notes on Fault Tree

1. MAP at idle should be (30-50) kPa, depending on engine load. BARO should be (85 to 105) kPa, depending on altitude. The difference between the two should always be greater than 11 kpa with the engine running at or near idle.
2. Check for vacuum at the throttle body with a vacuum gage. At idle, typical vacuum readings are (14"-20") Hg, depending on engine load.
3. PCM data PD02 should read 10-16 kPa with C127 disconnected. If PD02 reads greater than 16 kPa, check CKT 432 for a short to voltage.
4. Checking for a short to voltage inside the intake manifold.
5. Checking for short to voltage on CKT 469 or CKT 474. Also checking for high resistance on CKT 469. Disconnect C129 to eliminate 'voltage' from trans. temp. sensor return.