For a complete wiring diagram Refer to Section 8WWhen Monitored:With the ignition on and the Glow Plug Module Glow Plug command off.Set Condition:The ECM detects an open or shorted to ground on the Cylinder 1 Glow Plug circuit.Possible CausesINTERMITTENT DTC(A202) GLOW PLUG 1 CONTROL CIRCUIT OPEN(A202) GLOW PLUG 1 CONTROL CIRCUIT SHORTED TO GROUND(A202) GLOW PLUG 1 CONTROL CIRCUIT SHORTED TO VOLTAGEGLOW PLUG 1GLOW PLUG MODULEAlways perform the Pre-Diagnostic Troubleshooting procedure before proceeding.(Refer to 9 - ENGINE - DIAGNOSIS AND TESTING)1. CHECK FOR ACTIVE DTCIgnition on, engine not running.With the scan tool, clear DTCs in the Engine Control Module (ECM).Perform several ignition cycles leaving the ignition on for at least 10 seconds then off for 10 seconds.With the scan tool, read the ECM DTCs.Did this DTC set again?YesGo To2NoRefer to the *CHECKING FOR AN INTERMITTENT DTC Diagnostic Procedure.(Refer to 9 - ENGINE - DIAGNOSIS AND TESTING)2. (A202) GLOW PLUG 1 CONTROL CIRCUIT OPEN

Turn the ignition off.Disconnect the Glow Plug 1 harness connector.Disconnect the Glow Plug Module harness connector.Measure the resistance of the (A202) Glow Plug 1 Control circuit between the Glow Plug 1 harness connector and the Glow Plug Module harness connector.Is the resistance below 10.0 ohms?YesGo To3NoRepair the (A202) Glow Plug 1 Control circuit for an open.Perform the ECM Verification Test Ver. 1. (Refer to 9 - ENGINE - STANDARD PROCEDURE)3. (A202) GLOW PLUG 1 CONTROL CIRCUIT SHORTED TO GROUND

Measure the resistance between ground and the (A202) Glow Plug 1 Control circuit at the Glow Plug 1 harness connector.Is the resistance below 1000 ohms?YesRepair the (A202) Glow Plug 1 Control circuit for a short to ground.Perform the ECM Verification Test Ver. 1. (Refer to 9 - ENGINE - STANDARD PROCEDURE)NoGo To44. (A202) GLOW PLUG 1 CONTROL CIRCUIT SHORTED TO VOLTAGE

Turn the ignition on.Measure the voltage of the (A202) Glow Plug 1 Control circuit at the Glow Plug 1 harness connector.Is there voltage present on the (A202) Glow Plug 1 Control circuit?YesRepair the (A202) Glow Plug 1 Control circuit for a short to voltagePerform the ECM Verification Test Ver. 1. (Refer to 9 - ENGINE - STANDARD PROCEDURE)NoGo To55. GLOW PLUG 1Turn the ignition off.Refer to the Service Information and replace the Glow Plug 1.Turn the ignition on.With the scan tool, erase ECM DTC's.Perform several ignition key cycles leaving the ignition on for at least 10 seconds per cycle.With the scan tool, read ECM DTC's.Does the scan tool display this DTC?YesGo to 6NoTest complete.Perform the ECM Verification Test Ver. 1. (Refer to 9 - ENGINE - STANDARD PROCEDURE)6. GLOW PLUG MODULEUsing the wiring diagram/schematic as a guide, inspect the wiring and connectors between the Glow Plugs and the Glow Plug Module.Look for any chafed, pierced, pinched, or partially broken wires.Look for broken, bent, pushed out or corroded terminals.Refer to any Technical Service Bulletins that may apply.Were any problems found?YesRepair as necessary.Perform the ECM Verification Test Ver. 1. (Refer to 9 - ENGINE - STANDARD PROCEDURE)NoReplace the Glow Plug Module in accordance with the Service Information.Perform the ECM Verification Test Ver. 1. (Refer to 9 - ENGINE - STANDARD PROCEDURE)