SB18N001A

BULLETIN NUMBER:
SB18-N-001A
IMPORTANT SERVICE
INFORMATION FOR:
 SERVICE MANAGER
 SERVICE ADVISOR
 TECHNICIAN
 PARTS DEPARTMENT
 WARRANTY PERSONNEL
ISSUE DATE:
MAY 2019
GROUP:
ELECTRICAL
DTC U0106 LOST COMMUNICATION WITH GLOW PLUG CONTROL
MODULE (GPCM)
AFFECTED VEHICLES

2011-2018MY Isuzu N-Series Vehicles
Equipped with 5.2L 4HK1 Diesel Engines
This bulletin supersedes Service Bulletin SB18-N-001. Please discard previous
bulletin SB18-N-001.
CONDITION
Some customers may complain of an illuminated Check Engine Malfunction Indicator
Light (MIL) associated with Diagnostic Trouble Code (DTC) U0106, Lost Communication
with Glow Plug Control Module (GPCM). This condition may be the result of water
intrusion into the GPCM connector. Water from rain and other outside sources can pool
in the glow plug recessed area on the outside of the cylinder head. If enough water
accumulates, it can seep into the glow plug harness through the terminal ends and enter
the GPCM connector, causing this DTC to set.
If this DTC is found and evidence of water is present in the GPCM connector, replace the
glow plug harness terminals and rear panel cover as outlined in the service procedure in
this bulletin. The replacement terminal ends are sealed so that water cannot get into and
through the wire.
SERVICE PROCEDURE
1. Disconnect the negative battery terminal, chock the tires, and tilt the cab in
accordance with the directions in the applicable Workshop Manual (WSM), make
sure the tilt support locks in place and install the safety pin..
2. Remove the Air Inlet Hose from the Intercooler to the Throttle Body shown in
Figure 1, for access to the GPCM. (See Figure 2.)
Air Inlet Hose
GPCM
Figure 1
Figure 2
3. Inspect the GPCM harness connectors at the module (E-64 and E-65) for
moisture intrusion and damage to the connector or terminals. (See Figure 3.)
Figure 3
NOTE: Use shop air supply to blow away any moisture and debris found in the
connectors before proceeding.
4. Clean the connections with electrical contact cleaner.
5. Put dielectric grease in the GPCM connectors as shown in Figure 4 and
reconnect them to GPCM.
Figure 4
6. Disconnect EGR Gas Temperature Sensor 2 connector and remove the EGR
Cooler Duct and EGR Temperature Sensor 2 as an assembly. (See Figure 5.)
EGR Cooler Duct
EGR Temperature
Sensor 2
Figure 5
7. Disconnect the EGR valve connector and remove the EGR valve as shown in
Figure 6.
EGR Valve
Figure 6
8. At each individual glow plug wire, remove the nut that holds the terminal onto the
glow plug. Gently pull the wire with terminal end upwards. (See Figure 7.)
Remove the original harness clips as necessary to gain greater access. (See
Figure 8.)
Harness clip
Figure 7
Figure 8
9. Remove the original glow plug wire from the corrugated tubing.
Note: The corrugated tubing will be reused.
10. Cut off the original glow plug wire at approximately 60mm up from the glow plug
connection eyelet. (See Figure 9.) Discard the removed wire with eyelet.
Figure 9
11. Cut one of the new pigtail harness wires to the same length as the original wire
that was removed in Step 10 (approximately 60mm).
12. Strip 15mm of insulation off of the glow plug wire that remained on the engine
harness and 15mm of insulation off of the new pigtail wire that was cut in Step
11. (See Figure 10.) Slip a piece of shrink wrap at least 40mm long onto the
pigtail wire.
15mm
Figure 10
SPLICING WIRE
There are two types of splices that can be used: a solder or crimp type splice. Perform
only one type of splice per vehicle. The procedure for a Solder splice starts at Step 13
and for a Crimp splice starts at Step 17.
SOLDER TYPE SPLICE
13. Divide each of the stripped wire portions in two, join and then twist them together.
(See Figure 11.)
Figure 11
14. Solder the twisted wire joint together. Make sure that the soldered joint goes
completely around the wires and is at least 10mm in length. (See Figure 12.)
Figure 12
15. Slide the heat shrink tubing that was put on in Step 12 down over the soldered
joint and center it. Use a heat gun to heat and shrink the heat shrink tubing in
place. (See Figure 13.)
Heat Shrink Tubing
Figure 13
16. Repeat Steps 13 through 15 for each of the remaining three (3) glow plug
terminals. Once all terminals have been replaced, proceed to Step 21.
CRIMP TYPE SPLICE
NOTE: Use weatherproof type butt connectors that have adhesive on the inside of
the shrink tubing. Recommended connector size is 16-14 gauge, which is
normally blue in color.
17. Insert stripped wire from the new glow plug pig tail into solderless connector until
it reaches the center stop. Crimp the connector onto the pig tail harness.
18. Insert the pig tail with solderless connector onto the stripped wire from the glow
plug harness until it reaches the center stop. Crimp the connector onto the glow
plug harness. (See Figure 14.)
Figure 14
19. Apply heat to the connector to shrink the adhesive-lined shrink tubing. Wrap the
splice connection with electrical tape. (See Figure 15.)
Figure 15
20. Repeat Steps 17 through 19 for each of the remaining three (3) glow plug
terminals. Once all terminals have been replaced, proceed to Step 21.
21. Insert the glow plug wire back into the corrugated tubing removed in Step 9.
Tape the tubing in place using vinyl electrical tape. (See Figure 16.)
Figure 16
22. Install the new glow plug terminal onto the glow plug and torque the nut to 1.2
Nm (10.5 lb-in). (See Figure 17.) Replace any harness clips that were removed
to gain access.
Figure 17
23. Install the EGR valve and plug in the EGR valve connector. Torque bolts and
nuts to 23.5 Nm (17.3 lb-ft). (Figure 18.)
Figure 18
24. Install the EGR Cooler Duct and EGR Temperature Sensor 2 assembly. Plug in
the EGR Gas Temperature Sensor 2 connector to the harness. Torque the bolts
holding the EGR Cooler Duct to the EGR Valve to 23.5 Nm (17.3 lb-ft). Torque
the bolts holding the EGR Cooler Duct to the EGR Cooler to 28.4 Nm (21 lb-ft).
Torque the bolt holding the EGR Cooler Duct to the Cylinder Head to 48 Nm (35
lb-ft). (Figure 19.)
Figure 19
25. Install the Air Inlet Hose from the Intercooler to the Throttle Body. Tighten the Air
Inlet Hose clamps to 5 Nm (44 lb-in). (Figure 20.)
Air Inlet Hose
Figure 20
26. Connect the negative battery terminal.
27. Lower and lock the cab in place in accordance with the applicable WSM.
28. Start vehicle.
29. Clear DTC’s.
30. Cycle switch to “Key On” and check for proper glow plug operation.
31. Confirm no DTC’s are stored.
32. Cycle switch to “Off” position.
ENGINE COVER REPLACEMENT
33. Remove cab cover panel from the back of cab and set fasteners to the side for
re-use during installation. (See Figure 21.)
Figure - 21
34. Remove any fasteners remaining on removed cab cover and set them to the side
for re-use during installation. Figure 22 shows which fasteners are used for
installation of new cab cover.
Figure – 22 Circled brackets and bolts are NOT reused.
35. Install new lower brackets to the back of the cab.
36. Install new cab cover panel using fasteners set aside in Step 32. Upper mounting
bolts for the new cab cover panel will bolt directly into cab and the lower two
mounting points will mount to the new lower brackets. (See Figure 23.)
Figure - 23
PARTS INFORMATION
Part Number
Description
Qty
8-98386-783-0
Glow Plug Harness Pigtail
4
8-98106-027-1
EGR Valve Gasket
1
8-98106-025-1
EGR Valve Gasket
1
9-98200-753-0
Cooler Gasket
2
8-97508-934-0
Cab Cover Panel
1
8-97508-935-0
Back Panel Bracket
2
WARRANTY INFORMATION
For vehicles repaired under warranty, use:
Labor Operation Code
Description
Labor Time
N1732
Glow Plug Terminal
Replacement
1.1
Add Time: Replace Cab
Cover Panel
0.2