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Circuit Description

The ignition relay is a normally open relay. The relay armature is held in the open position by spring tension. When the ignition switch is turned to the run or start position, current will flow through the relay coil. A wire connected to the other end of the relay coil completes the path to ground. The electromagnetic field created by the relay coil, overcomes the spring tension and moves the armature allowing the relay contacts to close. The closed relay contacts allow current to flow from the battery to the following fuses:

When the ignition switch is turned to the OFF position, the electromagnetic field collapses. This action allows the spring tension to move the armature away from the relay contacts, which interrupts current flow to the fuses.

If the ignition relay fails to close, the engine will crank, but will not run. The class 2 communications will be available with the use of a scan tool.

The ignition relay table assumes that the vehicle battery is fully charged. Refer to Battery Inspection/Test (Non-HP2) in Engine Electrical.

Ignition Relay Diagnosis

Step Action Yes No
Schematic Reference:  Power Distribution Schematics  and  Ground Distribution Schematics  in Wiring Systems and  Engine Controls Schematics 
Connector End View Reference:  Engine Controls Connector End Views  or  Powertrain Control Module (PCM) Connector End Views 
1 Did you perform the Diagnostic System Check - Vehicle? Go to Step 2  Go to Diagnostic System Check - Vehicle in Vehicle DTC Information
2
  1. Turn ON the ignition, with the engine OFF.
  2. Remove the underhood junction block cover.
  3. Probe the following fuses with a test lamp that is connected to a good ground:
Does the test lamp illuminate on at least one test point of each fuse?		 Go to Step 3  Go to Step 10 
3
  1. Turn OFF the ignition.
  2. Probe both test points of the PCM 1 fuse with a test lamp that is connected to a good ground. Refer to Probing Electrical Connectors and Troubleshooting with a Test Lamp in Wiring Systems.
Does the test lamp illuminate on either test point of the fuse?		 Go to Step 4  Go to Step 30 
4
  1. Turn OFF the ignition.
  2. Remove the ignition 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.
    3. NOTE: Refer to Test Probe Notice in Cautions and Notices.
  3. Probe the ignition 1 voltage circuit of the ignition relay at the underhood junction block with a test lamp that is connected to a good ground. Refer to Probing Electrical Connectors and Troubleshooting with a Test Lamp in Wiring Systems.
Does the test lamp illuminate?		 Go to Step 7  Go to Step 5 
5 Test the relay load bus bar of the underhood junction block between the ignition relay and the fuses to the circuit components for a short to battery positive voltage. Refer to Circuit Testing in Wiring Systems.
Did you find a condition?		 Go to Step 29  Go to Step 6 
6
  1. Turn OFF the ignition.
  2. Remove the following fuses from the underhood junction block:
    • PCM 1
    • ETC/ECM
    • INJ 1
    • INJ 2
    • SBA, if equipped.
  3. Probe the above fuse terminals in the underhood junction block with a test lamp that is connected to a good ground. Refer to Probing Electrical Connectors and Troubleshooting with a Test Lamp in Wiring Systems.
Does the test lamp illuminate at any of the fuse terminals?		 Go to Diagnostic System Check - Vehicle in Vehicle DTC Information Go to Step 27 
7
  1. Turn OFF the ignition.
  2. Disconnect the negative battery cable at the battery. Refer to Battery Negative Cable Disconnect/Connect Procedure in Engine Electrical.
  3. Disconnect the underhood junction block electrical connector that contains the ignition 1 voltage circuit for the ignition relay.
  4. Disconnect the ignition switch electrical connector that contains the ignition 1 voltage circuit for the ignition relay.
  5. Connect the negative battery cable to the battery.
  6. Test the ignition 1 voltage circuit for a short to battery positive voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 Go to Step 30  Go to Step 8 
8
  1. Turn OFF the ignition.
  2. Probe the ignition 1 voltage terminal on the ignition switch side of the ignition switch electrical connector with a test lamp that is connected to a good ground. Refer to Probing Electrical Connectors and Troubleshooting with a Test Lamp in Wiring Systems.
Does the test lamp illuminate?		 Go to Step 28  Go to Step 9 
9 Test the ignition 1 voltage bus bar circuit in the underhood junction block for a short to battery positive voltage. Refer to Circuit Testing in Wiring Systems.
Did you find a condition?		 Go to Step 29  Go to Step 27 
10
  1. Turn OFF the ignition.
  2. Inspect the 40-amp IGN B fuse in the underhood junction block. Refer to Circuit Protection - Fuses in Wiring Systems.
Is the fuse open?		 Go to Step 11  Go to Step 18 
11
  1. Remove the 40-amp IGN B fuse from the underhood junction block.
    2. NOTE: Refer to Test Probe Notice in Cautions and Notices.
  2. Probe both fuse terminals in the underhood junction block with a test lamp that is connected to a good ground. Refer to Probing Electrical Connectors and Troubleshooting with a Test Lamp in Wiring Systems.
Does the test lamp illuminate on at least one fuse terminal?		 Go to Step 12  Go to Step 17 
12 Test the ignition 1 voltage circuit between the ignition switch and the underhood junction block for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 Go to Step 30  Go to Step 13 
13 Test the ignition switch assembly for a short to ground. Refer to Circuit Testing in Wiring Systems.
Did you find a condition?		 Go to Step 28  Go to Step 14 
14 Test the battery positive voltage circuit between the underhood junction block and the ignition switch for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 Go to Step 30  Go to Step 15 
15 Test the battery positive voltage bus bar circuit of the underhood junction block between the 40-amp IGN B fuse and the ignition switch for a short to ground.
Did you find a condition?		 Go to Step 29  Go to Step 16 
16 Test the ignition 1 voltage bus bar circuit of the underhood junction block that contains the ignition relay for a short to ground.
Did you find a condition?		 Go to Step 29  Go to Step 27 
17
  1. Turn OFF the ignition.
  2. Probe the mounting stud for the battery positive cable at the underhood junction block with a test lamp that is connected to a good ground. Refer to Probing Electrical Connectors and Troubleshooting with a Test Lamp in Wiring Systems.
Does the test lamp illuminate?		 Go to Step 29  Go to Diagnostic System Check - Vehicle in Vehicle DTC Information
18
  1. Turn OFF the ignition.
  2. Remove the ignition relay with the J 43244  from the underhood junction block. Refer to Relay Replacement (Within an Electrical Center) or Relay Replacement (Attached to Wire Harness) in Wiring Systems.
    3. NOTE: Refer to Test Probe Notice in Cautions and Notices.
  3. Probe the battery positive voltage circuit of the ignition relay at the underhood junction block with a test lamp that is connected to a good ground. Refer to Probing Electrical Connectors and Troubleshooting with a Test Lamp in Wiring Systems.
Does the test lamp illuminate?		 Go to Step 19  Go to Step 29 
19
  1. Turn ON the ignition, with the engine OFF.
  2. Probe the ignition 1 voltage circuit of the ignition relay at the underhood junction block with a test lamp that is connected to a good ground. Refer to Probing Electrical Connectors and Troubleshooting with a Test Lamp in Wiring Systems.
Does the test lamp illuminate?		 Go to Step 23  Go to Step 20 
20
  1. Turn OFF the ignition.
  2. Test the ignition 1 voltage circuit between the ignition switch and the underhood junction block for a high resistance or for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 Go to Step 30  Go to Step 21 
21 Test the ignition switch assembly for a high resistance or for an open. Refer to Circuit Testing in Wiring Systems.
Did you find a condition?		 Go to Step 28  Go to Step 22 
22 Test the battery positive voltage circuit between the ignition switch and the underhood junction block for a high resistance or for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 Go to Step 30  Go to Step 29 
23
  1. Turn ON the ignition, with the engine OFF.
  2. Probe the coil ground circuit of the ignition relay at the underhood junction block with a test lamp that is connected to battery voltage. Refer to Probing Electrical Connectors and Troubleshooting with a Test Lamp in Wiring Systems.
Does the test lamp illuminate?		 Go to Step 25  Go to Step 24 
24
  1. Turn OFF the ignition.
  2. Disconnect the negative battery cable at the battery. Refer to Battery Negative Cable Disconnect/Connect Procedure in Engine Electrical.
  3. Disconnect the underhood junction block electrical connectors.
  4. Test the coil ground circuit of the ignition relay at the underhood junction block electrical connector for a high resistance or for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 Go to Step 30  Go to Step 29 
25
  1. Turn OFF the ignition.
  2. Jumper the ignition relay battery positive voltage circuit and the ignition relay load circuit together at the underhood junction block with a 20-amp fused jumper wire. Refer to Using Fused Jumper Wires in Wiring Systems.
  3. Probe the following fuses with a test lamp that is connected to a good ground:
Does the test lamp illuminate on at least one test point of each fuse?		 Go to Step 26  Go to Step 29 
26 Test for an intermittent and for a poor connection at the underhood junction block, ignition relay connector location. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.
Did you find a condition?		 Go to Step 29  Go to Step 27 
27 Replace the ignition 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 30  -
28 Replace the ignition switch. Refer to Ignition Switch Replacement in Steering Wheel and Column.
Did you complete the replacement?		 Go to Step 30  -
29 Replace the underhood electrical center. Refer to Underhood Electrical Center or Junction Block Replacement in Wiring Systems.
Did you complete the replacement?		 Go to Step 30  -
30
  1. Replace any open fuses.
  2. Turn OFF the ignition for 30 seconds.
  3. Attempt to start the engine.
Does the engine start and run?		 Go to Step 31  Go to Engine Cranks but Does Not Run 
31
  1. Clear the DTCs with a scan tool.
  2. Operate the vehicle for 5 minutes.
Does a DTC set during this ignition cycle?		 Go to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC Information System OK
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