DTC 32

Code 32 Chart:

EGR System Schematic:

CIRCUIT DESCRIPTION:

The block learn controls the operation of the Exhaust Gas Recirculation (EGR) system. If the EGR system becomes inoperative, the inert exhaust gas would be replaced with ambient air, and the result of the air/fuel mixture would be leaner. The ECM tries to compensate for this condition by adding fuel, which results in higher block learn values.
The engine control system operates within sixteen block learn cells. Since EGR is not used at idle, the closed throttle cell would not be affected by the EGR system operation. The other block cells are affected by EGR operation, and when the EGR system is not operating properly, the block learn values in all cells should match fairly close. If the EGR system becomes inoperative, the block learn value in the open throttle cells would change to compensate for the resulting lean mixtures, but the block learn value in the closed throttle cell would not change. The change or difference in block learn values between the idle (closed throttle) cell and cell 10 is used to monitor EGR system performance. When the difference between two block learn values is greater than 12 and the block learn value in cell 10 is greater than 140, a Code 32 is set. The system operates in block learn cell 10 during a cruise condition, approximately 55 mph.


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 block learn cell 10, but not in the closed 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. See CHART C-1D.