On-Vehicle Service - GMC G Service Manual

Diagnostic Circuit Check. This will determine if the system
is operating correctly.
If the EGR system is not working properly, the Diesel
Diagnostic Circuit Check will direct diagnosis to a code
diagnosis or to another DEC system circuit.

ON-VEHICLE SERVICE

EGR VALVE REPLACEMENT (Figure 29)
M Remove or Disconnect
1. Air cleaner cover.
2. Vacuum hose (4) from the EGr valve.
3. Studs (2).
4. EGR valve (3).
K H Install or Connect
1. EGR valve (3).
2. Studs (2) (seal the studs with Loctite 272 or
equivalent).
3. Vacuum hose to EGR valve (3).
4. Air cleaner cover.
EPR VALVE REPLACEMENT (Figure 30)
H Remove or Disconnect
1. The vacuum hose from the actuator (2).
2. Clip from the valve lever.
3. Bolt holding the actuator to the valve.
4. Actuator from the EPR valve.
H
EGR/EPR SOLENOID ASSEMBLY REPLACEMENT
solenoid are replaced as an assembly. The vent filter can
be replaced as required. If diagnosis has determined that
any solenoid does not operate, replace with complete
assembly (Figure 31).
vent filters.
h 4! Remove or Disconnect (Figure 31)
M
Figure 31 — EGR/EPR Solenoid Assembly
DIESEL EMISSIONS 6E2-53
Install or Connect
1. Actuator (2) to the EPR valve.
2. Bolt.
3. Clip.
4. The vacuum hose.
The EGR solenoid, EGR vent solenoid, and the EPR
Refer to Maintenance Schedule for information about
1. Negative battery cables.
2. Electrical connectors from the solenoids.
3. Vacuum hoses from assembly (1 and 8).
4. EGR/EPR solenoid assembly (9).
Install or Connect (Figure 31)
1. EGR/EPR solenoid assembly (9).
2. Vacuum hoses to assembly (1 and 8).
3. Electrical connectors to the solenoids.
4. Negative battery cables.
5. Perform Diesel Diagnostic Circuit Check.
□ TO EPR VALVE
m VENT FILTER
TO MAP SENSOR
□ TO EGR VALVE
EGR SOLENOID
EGR VENT SOLENOID
m EPR SOLENOID
FROM VACUUM PUMP
| T | EGR/EPR SOLENOID ASSY
4S 1026-6EC