Diagnostic Aids

The DTC P0685 diagnostic table assumes that the vehicle battery is fully charged. Refer to Battery Inspection/Test in Engine Electrical.

DTC P0685

Step	Action	Values	Yes	No
Schematic Reference: Engine Controls Schematics and Power Distribution Schematics in Wiring Systems Connector End View Reference: Engine Controls Connector End Views and Electrical Center Identification Views in Wiring Systems
1	Did you perform the Diagnostic System Check - Vehicle?	-	Go to Step 2	Go to Diagnostic System Check - Vehicle in Vehicle DTC Information
2	Is DTC P0685 active?	-	Go to Step 3	Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems
3	Turn OFF the ignition. Remove the powertrain relay from the underhood junction block with the J 43244 Relay Puller Pliers. Refer to Relay Replacement (Within an Electrical Center) or Relay Replacement (Attached to Wire Harness) in Wiring Systems. NOTE: Refer to Test Probe Notice in Cautions and Notices. Probe the powertrain relay control circuit terminal at the underhood junction block with a test lamp that is connected to a good ground. Refer to Troubleshooting with a Test Lamp in Wiring Systems. Does the test lamp illuminate?	-	Go to Step 7	Go to Step 4
4	Turn ON the ignition, with the engine OFF. Probe the powertrain relay coil control circuit at the underhood junction block with a test lamp that is connected to a good ground. Does the test lamp illuminate?	-	Go to Step 5	Go to Step 9
5	Turn OFF the ignition. Disconnect the powertrain control module (PCM) electrical connector that contains the relay control circuit from the PCM. Refer to Powertrain Control Module (PCM) Replacement . Turn ON the ignition, with the engine OFF. Probe the powertrain relay control circuit terminal at the underhood junction block with a test lamp that is connected to a good ground. Refer to Probing Electrical Connectors in Wiring Systems. Does the test lamp illuminate?	-	Go to Step 6	Go to Step 12
6	Turn OFF the ignition. Disconnect the negative battery cable at the battery. Refer to Battery Negative Cable Disconnect/Connect Procedure in Engine Electrical. Disconnect the underhood junction block electrical connector that contains the powertrain relay coil control circuit. Refer to Underhood Electrical Center or Junction Block Replacement in Wiring Systems. Disconnect the powertrain relay control circuit wire terminal from the underhood junction block electrical connector. Connect the electrical connector that contained the powertrain relay coil control circuit to the underhood junction block. Connect the negative battery cable at the battery. Turn ON the ignition, with the engine OFF. Probe the powertrain relay control circuit wire terminal at the PCM electrical connector with a test lamp that is connected to a good ground. Refer to Probing Electrical Connectors in Wiring Systems. Does the test lamp illuminate?	-	Go to Step 13	Go to Step 15
7	Turn OFF the ignition. Disconnect the PCM electrical connector that contains the relay control circuit from the PCM. Refer to Powertrain Control Module (PCM) Replacement . Probe the relay coil control circuit terminal at the underhood junction block with a test lamp that is connected to a good ground. Does the test lamp illuminate?	-	Go to Step 8	Go to Step 12
8	Turn OFF the ignition. Disconnect the negative battery cable at the battery. Refer to Battery Negative Cable Disconnect/Connect Procedure in Engine Electrical. Disconnect the underhood junction block electrical connector that contains the powertrain relay control circuit. Refer to Underhood Electrical Center or Junction Block Replacement in Wiring Systems. Connect the negative battery cable at the battery. Probe the powertrain relay control circuit wire terminal at the underhood junction block electrical connector with a test lamp that is connected to a good ground. Does the test lamp illuminate?	-	Go to Step 13	Go to Step 15
9	Measure the resistance from terminal 30 of the relay to terminal 85 with a DMM. Refer to Troubleshooting with a Test Lamp in Wiring Systems. Does the DMM display the specified value?	infinity ohm	Go to Step 10	Go to Step 14
10	Measure the resistance from terminal 85 of the relay to terminal 87 with a DMM. Does the DMM display the specified value?	infinity ohm	Go to Step 11	Go to Step 14
11	Measure the resistance from terminal 85 of the relay to terminal 86 with a DMM. Does the DMM display the specified value?	70-110 ohm	Go to Step 17	Go to Step 14
12	Test for shorted terminals and poor connections at the PCM. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems. Did you find and correct the condition?	-	Go to Step 17	Go to Step 16
13	Repair the short to voltage in the powertrain relay control circuit between the underhood junction block electrical connector and the PCM electrical connector. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair?	-	Go to Step 17	-
14	Replace the powertrain relay. Refer to Relay Replacement (Within an Electrical Center) or Relay Replacement (Attached to Wire Harness) in Wiring Systems. Did you complete the replacement?	-	Go to Step 17	-
15	Replace the underhood junction block. Refer to Underhood Electrical Center or Junction Block Replacement in Wiring Systems. Did you complete the replacement?	-	Go to Step 17	-
16	Replace the PCM. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming. Did you complete the replacement?	-	Go to Step 17	-
17	Reassemble the vehicle as necessary. Replace any open fuses. Turn OFF the ignition for 30 seconds. Attempt to start the engine. Does the engine start and run?	-	Go to Step 18	Go to Engine Cranks but Does Not Run
18	Clear the DTCs with a scan tool. Operate the vehicle for 5 minutes. Does the DTC set during this ignition cycle?	-	Go to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC Information	System OK