Engine Control System
CODE 32 EXHAUST GAS RECIRCULATION (EGR) CIRCUITCode Chart 32:
EGR Valve Circuit:
CIRCUIT DESCRIPTION:
A properly operating EGR system will directly affect the air/fuel requirements of the engine. Since the exhaust gas introduced into the air/fuel mixture is an inert gas (contains very little or no oxygen), less fuel is required to maintain a correct air fuel ratio. If the EGR system were to become inoperative, the inert exhaust gas would be replaced with air and the air/fuel mixture would be leaner. The ECM would compensate for the lean condition by adding fuel, resulting in higher block learn values. The engine control system operates within two block learn cells, a closed throttle cell and an open throttle cell. Since EGR is not used at idle, the closed throttle cell would not be affected by EGR system operation. The open throttle cell is affected by EGR operation and when the EGR system is operating properly, the block learn values in both cells should be close to being the same. If the EGR system was inoperative, the block learn value in the open throttle cell would change (become higher) to compensate for the resulting lean system, but the block learn value in the closed throttle cell would not change. This change or difference in block learn values is used to monitor EGR system performance. Code 32 will set if the following two conditions are met:
^ If EGR valve fails to open or close.
^ If EGR valve gas temperature sensor opens or shorts to ground.
TEST DESCRIPTION: Numbers below refer to circled numbers on the diagnostic chart.
1. Checks for the gas temperature sensors 5.0 volt reference.
2. Looking for a poor or open ground wire.
3. Checks for short to voltage or ground in sensor 5.0 volts reference circuit.
4. Checking the EGR gas temperature sensors resistance.
5. A non-functioning EGR valve can cause Code 32 to set.
DIAGNOSTIC AIDS:
A poor connection or slewed EGR gas temperature sensor could cause a Code 32 to set.