The ignition relay supplies battery voltage to the following components:
• | The oxygen sensors (HO2S) |
• | The ignition control modules (ICM)/coils |
• | The fuel injectors |
• | The mass airflow (MAF) sensor |
The following may occur if the ignition relay fails to close:
• | Engine cranks, but does not run |
• | The scan tool data will be available. |
• | The instrument panel (IP) indicator will illuminate. |
The numbers below refer to the step numbers on the diagnostic table.
This step is testing the battery positive voltage circuit of the ignition relay.
This step is testing the ignition 1 positive voltage circuit of the ignition relay.
This step is testing the coil ground circuit of the ignition relay.
This step isolates the circuit from the ignition relay. All of the circuits at the relay are good if the test lamp illuminates.
Step | Action | Values | Yes | No | ||||||
---|---|---|---|---|---|---|---|---|---|---|
Schematic Reference: Engine Controls Schematics or Power Distribution Schematics and Ground Distribution Schematics in Wiring Systems | ||||||||||
1 | Did you perform the Diagnostic System Check-Engine Controls? | -- | Go to Step 2 | |||||||
Does the test lamp illuminate? | -- | Go to Step 3 | Go to Step 10 | |||||||
Does the test lamp illuminate? | -- | Go to Step 4 | Go to Step 6 | |||||||
Does the test lamp illuminate? | -- | Go to Step 5 | Go to Step 7 | |||||||
Important: At least one test point of each fuse must illuminate the test lamp.
Does the test lamp illuminate? | -- | Go to Step 8 | Go to Step 10 | |||||||
6 |
Did you find and correct the condition? | -- | Go to Step 11 | Go to Step 10 | ||||||
7 |
Did you find and correct the condition? | -- | Go to Step 11 | Go to Step 10 | ||||||
8 | Inspect for poor terminal contact at the ignition relay connector position of the underhood fuse block. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems. Did you find a condition? | -- | Go to Step 10 | Go to Step 9 | ||||||
9 | Replace the ignition Relay. Refer to Relay Replacement . Did you complete the replacement? | -- | Go to Step 11 | -- | ||||||
10 |
Important: Do not disassemble or attempt any repairs to the underhood fuse block. 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 11 | -- | ||||||
11 |
Does the vehicle operate normally, with no malfunction indicator lamp (MIL) illumination and no stored DTCs? | -- | System OK |