Observe DPFEGR PID at idle and compare to the key on engine off voltage. (A higher voltage at idle could be due to a non-seating EGR valve.)
Apply just enough vacuum to EGR valve to open it 7-10 kPa (2-3 in-Hg) without stalling engine and release vacuum. Repeat several times while observing DPFEGR PID. (DPFEGR PID voltage must increase as valve begins to open and return to initial value as vacuum is released. A slow to return voltage could be an indication of a binding or a slow-closing EGR valve.)
Does the DPFEGR PID voltage indicate an open, binding or slow-closing EGR valve? Yes
REMOVE and INSPECT the EGR valve for signs of contamination,
unusual wear, carbon deposits, binding and other damage. REPAIR as necessary.
No
KEY OFF. GO to HE32
.
HE32 MONITOR EGR VALVE VACUUM WHILE WIGGLING EGRVR CIRCUIT
Note: An intermittent short to GND in the EGRVR circuit will cause the vacuum applied to the EGR valve to be higher than normal while the short is present. The vacuum available at the EGR valve at idle is normally below 3.4 kPa (1.0 in-Hg) and it takes about 5.4 kPa (1.6 in-Hg) for the valve to begin to open.
Observe vacuum gauge for an indication of a fault while performing the following:
Lightly tap on the EGR vacuum regulator solenoid; wiggle the EGR vacuum regulator solenoid connector and vehicle harness between solenoid and PCM. A fault is indicated by a sudden jump in vacuum reading.
Is intermittent fault found? Yes
ISOLATE fault and REPAIR as necessary.
No
RECONNECT vacuum hose. KEY OFF. GO to HE33
.
HE33 INSPECT EGR VACUUM REGULATOR SOLENOID AND VACUUM HOSES FOR POTENTIAL PLUGGING
Remove EGR vacuum regulator solenoid vent filter and inspect for contamination and excessive water absorption. (In cold climate, excessive water in filter could freeze and plug the EGR vacuum regulator solenoid vent.)
Inspect EGR vacuum hose for possible blockage or pinching.
Is EGR vacuum regulator solenoid vent or filter contaminated or vacuum hose plugged? Yes
REPAIR EGR vacuum regulator solenoid or EGR vacuum hose as necessary.
HE72 RUN KOER SELF-TEST WHILE MONITORING EGR VACUUM
Disconnect vacuum hose at EGR valve and connect hose to a vacuum gauge.
Note: Since the EGR vacuum hose is disconnected, ignore DTCs during this KOER Self-Test.
Run Key On Engine Running (KOER) Self-Test while monitoring gauge. Approximately 30 seconds into test, EGR flow will be requested for a few seconds. The vacuum at this time should increase above 5.4 kPa (1.6 in-Hg) to open the valve.
Does the vacuum increase to 10 kPa (3.0 in-Hg) or greater at any time during KOER Self-Test? Yes
The vacuum indicated is sufficient to open the EGR valve. Fault
is unlikely to be in EGR vacuum control system. KEY OFF. GO to HE73
.
No
The vacuum indicated is insufficient to open the EGR valve.
Slowly apply 27 to 34 kPa (8 to 10 in-Hg) of vacuum to the EGR valve and hold it for 10 seconds. If engine wants to stall, increase rpm with throttle to maintain a minimum of 1000 rpm.
Look for the following:
EGR valve starts opening at about 5.4 kPa (1.6 in-Hg) vacuum indicated by increasing DPFEGR PID voltage.
DPFEGR PID voltage increasing until EGR valve is fully open. DPFEGR PID must read 2.5 volts minimum with full vacuum applied.
DPFEGR PID voltage steady when vacuum is held. If voltage drops within a few seconds, the EGR valve or vacuum source can be leaking.
Does the DPFEGR PID voltage indicate that the EGR valve is operating as described in this test? Yes
GO to HE85
.
No
REMOVE and INSPECT the EGR valve for signs of contamination,
unusual wear, carbon deposits, binding, leaking diaphragm and other damage.
If EGR valve is OK, look for an obstructed EGR port in the intake manifold
or plugged orifice tube assembly. REPAIR as necessary.
HE80 CHECK VACUUM SOURCE AND VACUUM HOSES TO AND FROM EGR VACUUM REGULATOR SOLENOID
Inspect vacuum lines between vacuum source and EGR vacuum regulator solenoid and between EGR vacuum regulator solenoid and EGR valve for leaks, kinks, disconnects, blockage, routing or any damage.
Disconnect vacuum hoses at EGR vacuum regulator solenoid.
Connect EGR vacuum regulator solenoid vacuum source hose to a vacuum gauge.
With engine warm and at idle, take vacuum gauge reading.
Is the vacuum gauge reading a minimum of 51 kPa (15 in-Hg) at idle and vacuum lines OK? Yes
KEY OFF. GO to HE81
.
No
ISOLATE fault and REPAIR as necessary.
HE81 CHECK VPWR VOLTAGE TO EGR VACUUM REGULATOR SOLENOID
Disconnect EGR vacuum regulator solenoid.
Key on, engine off.
Measure VPWR circuit voltage at EGR vacuum regulator solenoid harness connector.
Is EGR vacuum regulator solenoid VPWR voltage greater than 10.5 volts? Yes
Slowly apply 17 to 34 kPa (5 to 10 in-Hg) of vacuum to the EGR valve and hold it for 10 seconds. If engine wants to stall, increase rpm with throttle to maintain a minimum of 800 rpm.
Look for the following:
EGR valve starts opening at about 5.4 kPa (1.6 in-Hg) vacuum indicated by increasing DPFEGR PID voltage.
DPFEGR PID voltage increasing until EGR valve is fully open. DPFEGR PID should read 2.5 volts minimum with full vacuum applied.
DPFEGR PID voltage steady when vacuum is held. If voltage drops within a few seconds, the EGR valve or vacuum source could be leaking.
Does the DPFEGR PID voltage indicate that the EGR valve is operating as described in this test? Yes
GO to HE94
.
No
REMOVE and INSPECT the EGR valve for signs of contamination,
unusual wear, carbon deposits, binding, leaking diaphragm and other damage.
If EGR valve is OK, look for an obstructed EGR port in the intake manifold.
REPAIR as necessary.
HE94 INSPECT EGR VACUUM SIGNAL SUPPLY FOR INTERMITTENT FAILURE
Disconnect plugged hose at EGR valve and connect to a vacuum gauge.
Key on, engine running.
Connect a jumper wire between EGRVR circuit and ground to activate the solenoid to full on. At idle, the vacuum gauge should read above 13.5 kPa (4.0 in-Hg).
Observe vacuum gauge for an indication of a fault while performing the following:
Lightly tap on the EGR vacuum regulator solenoid and wiggle the EGR vacuum regulator solenoid connector, vacuum lines and vehicle harness between the solenoid and PCM. A fault is indicated by a sudden drop in vacuum reading.
Is a fault indicated? Yes
ISOLATE fault and REPAIR as necessary.
No
Unable to duplicate or identify fault at this time. (In cold
HE100 EGR DIAGNOSIS BY SYMPTOM: CHECK FOR EGR FLOW WITH EGR VACUUM HOSE DISCONNECTED AND PLUGGED
Note: Perform KOER Self-Test and repair any DTCs before proceeding with this test.
The symptom charts have indicated possible EGR flow at idle with no EGR diagnostic trouble codes output.
Possible causes:
Disconnect vacuum hose at EGR valve and plug hose.
Key on, engine off.
Access DPFEGR PID and note voltage.
Start engine and bring to idle.
With engine at idle, look at the DPFEGR PID voltage and compare to the engine off reading. An increase in the voltage at idle indicates that the differential pressure feedback EGR sensor is sensing EGR flow.
Is the DPFEGR PID voltage greater at idle by a minimum of 0.15 volt than with the engine off? Yes
The DPFEGR PID voltage is indicating EGR flow at idle. Since
the EGR vacuum hose is disconnected and plugged, the fault is most likely
in the EGR valve. REMOVE and INSPECT the EGR valve for signs of contamination,
unusual wear, carbon deposits, binding and other damage. REPAIR as necessary.
No
This indicates a fault in the EGR valve vacuum supply. INSPECT
the EGR vacuum regulator solenoid vent and vent filter for restrictions. REPAIR
as necessary. If OK, REPLACE EGR vacuum regulator solenoid.
Note: Refer to the PCM connector pin numbers in the beginning of this pinpoint test. Note: If DTC P1409 was output in Key On Engine Off (KOEO) or Key On Engine Running (KOER) Self-Test, GO to HE110 to diagnose present fault.
Disconnect PCM.
Key on.
Measure voltage between EGRVR and PWR GND circuits at the PCM harness connector.
Voltage must read greater than 10.5 volts. For an indication of a fault, look for this voltage to drop while performing the following:
Lightly tap on the EGR vacuum regulator solenoid.
Wiggle the EGR vacuum regulator solenoid connector.
Grasp the EGR vacuum regulator solenoid harness connector and wiggle wires between solenoid and PCM.