Powertrain Controls - ECM/PCM

DTC 76:

EGR Schematic:

CIRCUIT DESCRIPTION
Exhaust Gas Recirculation (EGR) is administered through a digitally controlled 3 solenoid valve unit. Each of the 3 valves is controlled individually and can be open or closed in any combination. During a long closed throttle deceleration, the Powertrain Control Module (PCM) will cycle each valve open and measure a change in Manifold Absolute Pressure (MAP). This test indicates if the valve is nonoperational electrically, or if an EGR passage is obstructed. If the PCM does not detect a change in MAP associated with solenoid # 2 being commanded "ON," a Diagnostic Trouble Code (DTC) 76 will be set.

DTC 76 WILL SET WHEN
The engine speed is between 14O0 and 2000 RPM, MAP is between 20 and 30 kPa, throttle position sensor angle is at 0%, all values must be held fairly constant for the test to run. The test must fail 3 consecutive times for a DTC 76 to be set.

ACTION TAKEN (PCM) WILL DEFAULT TO
The Malfunction Indicator Lamp (MIL) will become illuminated.

DTC 76 WILL CLEAR WHEN
The current DTC 76 will clear after each ignition key cycle, and will only reset when the test is run and fails again. A History DTC 76 will clear after 50 consecutive ignition key cycles without a current DTC 76 being stored.

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

1. This test determines if there is power to the EGR valve.
2. This test will determine of there is an open circuit in the EGR wiring or if the EGR valve is at fault.
3. This test will determine if there is a short to ground in circuit 698 going to the EGR valve or if the PCM is at fault.
4. Check for an open "ERLS" fuse. If open, check branch circuits and components for short to ground or internally shorted components.

DIAGNOSTIC AIDS
An intermittent may be caused by a poor connection, chaffed wire insulation, or a wire broken inside the insulation.
The intake plenum should be checked for possible plugged passages.