Linear EGR System (NB6 Option)

Linear EGR Wiring.:

LINEAR EXHAUST GAS RECIRCULATION (EGR) SYSTEM

The PCM controls the amount of EGR flow by sending a PWM ground signal to a linear EGR module (EGR valve signal modifier module assembly). Since the PCM does not have the capability to control the valve directly the linear EGR module reads the PCM, amplifies the signal to operate the valve.

The EGR solenoid also incorporates a position feedback circuit which sends a signal to the PCM indicating the location of the pintle. This sensor provides closed loop control of EGR as well as diagnostics. When the valve is closed the normal pintle position voltage should be between 0.3 and 1.2 volts.



EGR FUNCTIONAL TESTING



1. By grounding circuit 697 with a fused jumper at the EGR module, the EGR module should command the linear valve all the way open. This may result in a DTC 26 or 27 when performed with engine running. Clear codes when testing is done.

2. If the engine starts to run rough or stalls when commanding EGR full on, it indicates the system is functioning properly at this time. If RPM does not change, but the pintle position moved in step 1, it indicates the passages may be plugged. At this point, the valve must be removed and possible restrictions corrected.

3. To verify that the PCM is commanding the EGR valve on:
a. Raise Drive wheels.
b. Engine at normal operating conditions.
c. Start engine and put in "Drive".
WARNING: Use extreme caution due to spinning tires. If vehicle lowers during the test, the vehicle may uncontrollably accelerate when the spinning tires contact the ground.
d. Accelerate vehicle while observing voltage at terminal "A" of EGR valve.
e. Shut engine, wait for tires to stop spinning and lower vehicle.