Part 1 of 3
Code 32 Chart - Part 1 Of 3.:
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.
A scan tool can be used to monitor the position feedback voltage. This parameter is located in the General Information table. The following parameters can be found in the Fuel and Emission table.
^ % EGR - Indicates the amount of EGR as calculated by the ECM.
^ Desired Position - Percent EGR pintle opening commanded by the PCM.
^ Actual Position - Percent open of the EGR pintle.
DTC PARAMETERS
There are two different parts to DTC 32 A and B.
A. Under certain driving conditions the PCM will turn off the signal to the module causing the EGR valve to close. The PCM then monitors the oxygen sensor and how much affect it has on the short term fuel trim. If the fuel trim does not move a calibrated amount and the test fails three times in a row, a DTC 32 will set.
This test is performed when:
^ MAP is between 25 and 65 kPa (172 and 448 psi).
Note: At altitude MAP may differ up to 15 kPa (103 psi).
^ VSS is above 32 km/H (20 mph).
^ 20% Desired pintle position.
^ TP sensor is between 5 and 50% and steady.
^ 8 Count integrator change must occur within five seconds.
B. The PCM constantly monitors the position feedback signal. DTC 32 will set if the voltage is ever below 0.10 volts or if the actual position does not closely match the desired position after 25 seconds (10% or 26 counts).
TEST DESCRIPTION
1. Vehicle speed is required to turn EGR on. When all the conditions are met to command EGR on. it will be indicated by the desired position. This step will verify EGR control as well as the ability of the position sensor to feedback information to the PCM. Be sure DTC 32 is not currently set when running this test.
IMPORTANT: This test may result in an ABS code. Percent open values that are displayed for actual and desired position may van slightly.
2. By grounding circuit 697 the EGR module should command the linear valve all the way open. This will result in a DTC 26 or 27 when performed with engine running.
3. 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.
4. This step will determine if the EGR module has the ability to pull to ground circuit 698.