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 fuel 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.


TEST DESCRIPTION: The numbers below refer to circled numbers on the diagnostic chart.

1. A Code 32 will set under these conditions:
^ Block learn values is in cell 10 and over 140 counts.
^ Block learn difference between cell 0 (idle) and cell 10 (55 mph cruise) is greater than 12 counts.
^ For longer than 255 seconds.


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.