GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2001 🢒 Corvette 🢒 Engine 🢒 Engine Electrical 🢒 Ignition Relay Diagnosis

Circuit Description

The ignition relay supplies voltage to the following components:

    • The ignition control modules (ICM)
    • The fuel injectors
    • The powertrain control module (PCM)
    • The mass airflow (MAF) sensor
    • Transmission control solenoids
    • The A/C clutch relay

Diagnostic Aids

If the ignition relay fails to close, the following will occur:

    • The engine cranks, but does not run
    • The scan data will be available
    • The instrument panel lamps will illuminate

Test Description

The numbers below refer to the step numbers on the diagnostic table:

  1. This step tests the battery positive voltage circuit of the ignition relay.

    2.

  2. This step tests the ignition 1 positive voltage circuit of the ignition relay.

    3.

  3. This step tests the coil ground circuit of the ignition relay.

    4.

  4. This step isolates the circuit from the ignition relay. All of the circuits at the relay are good if the test lamp illuminates.

Ignition Relay Diagnosis

Step

Action

Value(s)

Yes

No

Schematic Reference: Engine Controls Schematics , Power Distribution Schematics , and Ground Distribution Schematics

1

Did you perform the Diagnostic System Check-Engine Controls?

--

Go to Step 2

Go to Diagnostic System Check - Engine Controls

2

  1. Turn OFF the ignition.
  2. Remove the underhood fuse block cover.
  3. Remove the ignition relay with the J 43244 Relay Puller Pliers.
  4. Probe the battery positive voltage circuit of the ignition relay at the underhood fuse block with the test lamp connected to a good ground. Refer to Troubleshooting with a Test Lamp in Wiring Systems.

Does the test lamp illuminate?

--

Go to Step 3

Go to Step 6

3

  1. Turn ON the ignition, with the engine OFF.
  2. Probe the ignition 1 voltage circuit of the ignition relay at the underhood fuse block with the test lamp connected to a good ground.

Does the test lamp illuminate?

--

Go to Step 4

Go to Step 7

4

  1. Turn ON the ignition, with the engine OFF.
  2. Probe the coil ground circuit of the ignition relay at the underhood fuse block with the test lamp connected to a B+.

Does the test lamp illuminate?

--

Go to Step 5

Go to Step 7

5

  1. Turn OFF the ignition.
  2. Jumper the ignition relay battery positive voltage circuit and the ignition relay load circuit together at the underhood fuse block, using fused jumper wires . Refer to Using Fused Jumper Wires in Wiring Systems.

    3. Important: Important

    At least one test point of each fuse must illuminate the test lamp.

  3. Probe the following fuses with the test lamp connected to a ground.
    4. • ENG IGN 1
    • INJR 1
    • A/C

Does the test lamp illuminate?

--

Go to Step 10

Go to Step 9

6

Repair the open or short to ground in the battery positive voltage circuit of the ignition relay. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

--

Go to Step 12

--

7

Repair the open or short to ground 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 12

--

8

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 12

--

9

Repair the high resistance, open, or short to ground in the ignition relay load circuit. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

--

Go to Step 12

--

10

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 and correct the condition?

--

Go to Step 12

Go to Step 11

11

Replace the ignition relay.

Did you complete the replacement?

--

Go to Step 12

--

12
  1. Clear the DTCs with a scan tool.
  2. Turn OFF the ignition for 30 seconds.
  3. Start the engine.
  4. Operate the vehicle for 5 minutes.

Does the vehicle operate normally, with no malfunction indicator lamp (MIL) illumination and no stored DTCs?

--

System OK

Go to Diagnostic Trouble Code (DTC) List