DTC 32

Code 32 Chart:

EGR System Schematic:

CIRCUIT DESCRIPTION:

A properly operating EGR system will directly affect the air/fuel mixture requirements of the engine. Since the exhaust gas introduced into the air/fuel mixture cannot be used in combustion (contains very little oxygen), less fuel is required to maintain a correct air/fuel ratio. If the EGR system were to fail in a closed position, the 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 open throttle cells. Since EGR is not used at idle, the closed throttle cell would not be affected by the EGR system operation. The open throttle cell is affected by EGR operation, and when the EGR system is not operating properly, the block learn values in both cells should match fairly close. If the EGR system was inoperative, the block learn value in the open throttle cell would change to compensate for the resulting lean system, but the block learn value in the closed throttle cell would not change. The change or difference in block learn value is used to monitor EGR system performance. When the change becomes too great, a Code 32 is set.



DIAGNOSTIC AIDS:

1. The Code 32 chart is a functional check of the EGR system. If the EGR system works properly, but a Code 32 has been set, check other items that could result in high block learn values in the open throttle cell.
2. CHECK: EGR passages for a restriction. If a restriction exist, see MAINTENANCE PROCEDURES under EMISSION CONTROLS.
3. CHECK: MAP sensor for a shift in calibration that may affect fuel delivery. Refer to Chart C-1D, Manifold Absolute Pressure (MAP) Sensor Check.