Note: Follow this procedure if the engine does not start cold, with or without GLOW PLUGS lamp operation.
1. Check the following items:
• Fuel system (must check OK)
• Cranking/charging system (battery must have 12.4 volts minimum)
• Cranking speed (100 rpm minimum)
2. Check voltage at the controller/relay terminal stud (battery side) (refer to Figure 8-21, view A):
• If voltage measured is battery voltage, go to step 3.
• If voltage measured is zero, repair the circuit from the battery to the relay terminal stud and check
system operation.
3. Check voltage at the controller/relay terminal stud (glow plug side) (refer to Figure 8-21, view B):
• If voltage measured is zero, go to step 4.
• If voltage measured is battery voltage, replace the controller/relay (shorted relay contacts) and all glow plugs, then check system operation.
4. Disconnect all glow plug wires and measure glow plug resistance (refer to Figure 8-21, view C):
• If each glow plug has a resistance less than 1 ohm, go to step 5.
• If any glow plug has a resistance greater than 1 ohm, replace it and check system operation.
Note: After step 4, reconnect all glow plug wires.
Refer to the following reference chart, if necessary:
5. Remove the controller circuit electrical connector, move the ignition switch to RUN and measure the voltage at terminal D (harness side) (refer to Figure 8-22, view A):
• If voltage measured is battery voltage, go to step 6.
• If voltage measured is zero, repair the circuit from the ignition switch to terminal D and check
system operation.
Note: After step 5, move the ignition switch to OFF.
6. With the controller circuit electrical connector removed, measure the resistance between terminal E (harness side) and the cylinder case (refer to Figure 8-22, view B):
• If resistance measured is less than 1 ohm, go to step 8.
• If resistance measured is more than 1 ohm, repair the circuit from terminal E and the vehicle ground and check system operation.
7. With the controller circuit electrical connector removed, measure the resistance between terminals C and E (harness side) (refer to Figure 8-22, view C):
• If resistance measured is less than 2 ohms, go to step 8.
• If resistance measured is more than 2 ohms, repair the circuit from the glow plug wiring harness to terminal C and check system operation.
Note: After step 7, reconnect the controller circuit electrical connector.
Refer to the following reference chart, if necessary:
8. Move the ignition switch to RUN while measuring the voltage at the controller/relay terminal stud (glow plug side) (refer to Figure 8-23, view A):
• If voltage measured is battery voltage, go to step 9.
• If voltage measured is zero, replace the glow plug controller/relay and check system operation.
9. Move the ignition switch to RUN while measuring the voltage at any glow plug on each cylinder bank (refer to Figure 8-23, view B):
• If voltage measured is battery voltage, go to step 10.
• If voltage measured is zero, repair the circuit between the controller/relay and glow plugs, then check
system operation.
10. Note GLOW PLUGS lamp operation (refer to Figure 8-23, view C):
• If the lamp does not cycle on and off when the controller/relay cycles, repair the lamp circuit and check system operation.
• If the lamp cycles on and off, end the diagnosis.
Refer to the following reference chart, if necessary:
