Automatic Glow Time Module and Glow Plugs, Checking
Automatic Glow Time Module and Glow Plugs, Checking
Observe all safety precautions: => [ Safety Precautions ] Generic Scan Tool
View clean working conditions: => [ Clean Working Conditions ] Clean Working Conditions
Prior to repair work, perform a preliminary check to verify the condition. Refer to => [ Preliminary Check ] Preliminary Check.
Use only gold-plated terminals when servicing any component with gold-plated electrical harness connector terminals.
For wiring diagrams, component locations, and connector views, Refer to the applicable wiring diagram.
Special tools, testers and auxiliary items required
• Multimeter
• Wiring diagram
Test requirements
• A/C switched off
• All electrical consumers switched off
• Battery voltage at least 12.5 volts
• Engine control module fuses OK
• Ground connections between engine/transmission/chassis OK
• Ignition switched off
• Vehicles with automatic transmission, shift selector lever in park or neutral
Start diagnosis
- The Automatic Glow Time Control Module (J179) is a relay located in the underhood fuse box and can be viewed by removing the cover of the fuse box and remove the automatic glow time control module (relay A3).
- Disconnect the Automatic Glow Time Control Module (J179) (relay) connector.
Checking voltage
Ignition switched ON.
- Using a multimeter with BLACK lead connected to engine ground, measure the voltage of terminal 11 (relay terminal 30) and then 5 (relay terminal 87) of the Automatic Glow Time Control Module (J179) black (relay) harness connector.
Specified value for each terminal: Battery voltage.
If the specified value was obtained:
- Using a multimeter with the RED lead connected to Battery Positive, measure the ground of terminal 7 (relay terminal 31) of the Automatic Glow Time Control Module (J179) black (relay) harness connector.
Specified value: Battery voltage.
Ignition switched OFF.
If the any of the specified values were not obtained:
- Check the circuit for an short to ground, open or high resistance.
- Check the electrical harness connector for damage, corrosion, loose or broken terminals.
- Replace any blown fuses.
- Repair as necessary.
If the specified value was obtained:
Ignition switched ON.
- Using a multimeter with BLACK lead connected to engine ground, measure the voltage at terminal 10 (relay terminal ST) of the Automatic Glow Time Control Module (J179) black (relay) harness connector.
Specified value: 3.44 V (+/-.5 V)
If the specified value was obtained:
- Using a multimeter with BLACK lead connected to engine ground, measure the voltage at the terminal 9 (relay terminal D1) of the Automatic Glow Time Control Module (J179) black (relay) harness connector.
Specified value: 10.74 V (+/-.8 V)
If the voltage readings were correct:
Ignition switched OFF.
- Replace the Automatic Glow Time Control Module (J179) (relay).
If any of the specified values were not obtained:
- Remove the Engine Control Module (ECM) (J623). Refer to the Repair Manual.
- Using a multimeter, check the Automatic Glow Time Control Module (J179) electrical harness connector to the Engine Control Module (ECM) (J623) electrical harness T91 connector for resistance.
Remove Positive battery cable when testing resistance on these circuits.
Specified value: 1.5 ohms Max.
If the specification was Not obtained:
- Check the wiring for a short circuit to each other, Battery positive, Ground or high resistance.
- If necessary, repair the faulty wiring connection.
- Check the electrical harness connector for damage, corrosion, loose or broken terminals.
If no malfunction is detected in the wiring and the voltage readings were Not correct:
- Replace the Engine Control Module (ECM) (J623).
Checking Glow Plugs
Engine must be cool to touch or resistance values will be affected.
- Using a multimeter, check the resistance of each glow plug at the Automatic Glow Time Control Module (J179) black (relay) harness connector to engine ground (with the glow plugs connected). These are identified as 1, 2. 3, 4, 5, 8 on the black (relay) harness connector (or G1 - G6 identified on relay) and correspond to Glow Plug 1,2,3,4,5,6.
Specified value: 1.3 ohms Max. each glow plug (0.6 ohms for Glow Plug, 0.2 ohms for wiring).
If the specified value was not obtained:
- Check the glow plug or circuit for a short, open circuit or high resistance.
• The Glow Plug terminal/connector is not repairable. The harness must be replaced if damaged. The relay terminals can be repaired.
- Check the electrical harness connector for damage, corrosion, loose or broken terminals.
- Repair/replace as necessary.
Final procedures
After repair work, the following work steps must be performed in the following sequence:
1. Check the DTC memory. Refer to => [ Diagnostic Mode 03 - Read DTC Memory ] Diagnostic Modes 01 - 09.
2. If necessary, erase the DTC memory. Refer to => [ Diagnostic Mode 04 - Erase DTC Memory ] Diagnostic Modes 01 - 09.
3. If the DTC memory was erased, generate readiness code. Refer to => [ Readiness Code ] Programming and Relearning.