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:
• | Eng Devices |
• | Oxy Sensors |
• | DFI/MDL |
• | Trans Sol |
• | A/C Relay Fuse |
• | Fuel Inj |
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 in Engine Electrical.
Step | Action | Yes | No | ||||||||||||
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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 Connector End Views | |||||||||||||||
1 | Did you perform the Diagnostic System Check - Engine Controls? | Go to Step 2 | |||||||||||||
2 |
Does the test lamp illuminate on at least one test point of each fuse? | Go to Step 3 | Go to Step 11 | ||||||||||||
3 |
Does the test lamp illuminate on either test point of the fuse? | Go to Step 4 | Go to Step 33 | ||||||||||||
4 |
Does the test lamp illuminate? | Go to Step 7 | Go to Step 5 | ||||||||||||
5 | Test the ignition relay load circuit between the ignition relay and the fuses to the circuit components 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 33 | Go to Step 6 | ||||||||||||
6 |
Does the test lamp illuminate at any of the fuse terminals? | Go to Diagnostic System Check - Engine Electrical in Engine Electrical | Go to Step 30 | ||||||||||||
7 |
Did you find and correct the condition? | Go to Step 33 | Go to Step 8 | ||||||||||||
8 | Test the ignition 1 voltage buss bar in the left I/P junction block for a short to battery positive voltage. Refer to Circuit Testing in Wiring Systems. Did you find a condition? | Go to Step 32 | Go to Step 9 | ||||||||||||
9 |
Did you find and correct the condition? | Go to Step 33 | Go to Step 10 | ||||||||||||
10 |
Does the test lamp illuminate? | Go to Step 31 | Go to Step 30 | ||||||||||||
11 |
Does the test lamp illuminate on both test points of the fuse? | Go to Step 14 | Go to Step 12 | ||||||||||||
12 | Test the battery positive voltage circuit between the ignition relay and the underhood #2, 60 amp MAXI fuse 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 33 | Go to Step 13 | ||||||||||||
13 | Test the relay load circuit between the ignition relay and the fuses to the circuit components 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 33 | Go to Step 30 | ||||||||||||
14 |
Does the test lamp illuminate on both test points of the fuse? | Go to Step 20 | Go to Step 15 | ||||||||||||
15 | Does the test lamp illuminate on one test point of the ABS/PCM fuse? | Go to Step 16 | Go to Step 17 | ||||||||||||
16 |
Did you find and correct the condition? | Go to Step 33 | Go to Step 18 | ||||||||||||
17 |
Does the test lamp illuminate? | Go to Step 32 | Go to Step 19 | ||||||||||||
18 | Test the ignition 1 voltage buss bar in the left I/P junction block for a short to ground. Refer to Circuit Testing in Wiring Systems. Did you find a condition? | Go to Step 32 | Go to Step 30 | ||||||||||||
19 |
Did you find and correct the condition? | Go to Step 33 | Go to Step 31 | ||||||||||||
20 |
Does the test lamp illuminate? | Go to Step 21 | Go to Step 26 | ||||||||||||
21 |
Does the test lamp illuminate? | Go to Step 22 | Go to Step 25 | ||||||||||||
22 |
Does the test lamp illuminate? | Go to Step 23 | Go to Step 28 | ||||||||||||
23 |
Does the test lamp illuminate on at least one test point of each fuse? | Go to Step 24 | Go to Step 29 | ||||||||||||
24 | Test for an intermittent and poor connection at the underhood bottom junction block, ignition relay connector location. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct a condition? | Go to Step 33 | Go to Step 30 | ||||||||||||
25 | Test the ignition 1 voltage buss bar circuit in the left I/P junction block between the 10 amp ABS/PCM fuse and the ignition relay for an open. Refer to Circuit Testing in Wiring Systems. Did you find a condition? | Go to Step 32 | Go to Step 27 | ||||||||||||
26 | Repair the high resistance or an open in the battery positive voltage circuit to the ignition relay. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 33 | -- | ||||||||||||
27 | Repair the high resistance or an open in the ignition 1 voltage circuit of the ignition relay. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 33 | -- | ||||||||||||
28 | Repair the high resistance or an open in the ground circuit of the ignition relay. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 33 | -- | ||||||||||||
29 | Repair the high resistance or an open in the load circuit of the ignition relay. Refer to Wiring Repairs in Wiring Systems Did you complete the repair? | Go to Step 33 | -- | ||||||||||||
30 | Replace the ignition relay. Refer to Relay Replacement in Wiring Systems. Did you complete the repair? | Go to Step 33 | -- | ||||||||||||
31 | Replace the ignition switch. Refer to Ignition and Start Switch Replacement in Instrument Panel, Gages, and Console. Did you complete the repair? | Go to Step 33 | -- | ||||||||||||
32 | Replace the left instrument panel junction block. Refer to Underhood Electrical Center or Junction Block Replacement in Wiring Systems. Did you complete the repair? | Go to Step 33 | -- | ||||||||||||
33 |
Does the engine start and run? | Go to Step 34 | |||||||||||||
34 |
Do the DTCs set during this ignition cycle? | System OK |