GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2002 🢒 Impala 🢒 Engine 🢒 Engine Controls - 3.8L 🢒 Ignition Relay Diagnosis

Circuit Description

The ignition relay supplies voltage to the following components:

    • The oxygen sensors
    • The powertrain control module (PCM)
    • The ignition control (IC) module
    • The A/C CLU Relay

Diagnostic Aids

If the ignition relay fails to close:

    • The scan data will be available.
    • The vehicle will crank, no start.
    • The dash indicator lights will illuminate.

Test Description

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

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

    2.

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

    3.

  3. This step is testing the relay ground circuit.

    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

Yes

No

Schematic Reference: Power Distribution Schematics , and Ground Distribution Schematics in Wiring Systems, and Engine Controls 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 relay center 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 relay center with the test lamp connected to a ground. Refer to Probing Electrical Connectors in Wiring Systems.

Does the test lamp illuminate?

Go to Step 3

Go to Step 8

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 relay center with a test lamp connected to a good ground.

Does the test lamp illuminate?

Go to Step 4

Go to Step 9

4

  1. Turn ON the ignition, with the engine OFF.
  2. Probe the ignition main relay ground connector terminal with a test lamp connected to 12 volts.

Does the test lamp illuminate?

Go to Step 5

Go to Step 10

5

  1. Turn OFF the ignition.
  2. Jumper the battery positive voltage circuit of the ignition relay and the ignition relay load circuit together using a fused jumper wire.
  3. Probe the following fuses with the test lamp connected to a ground.
    4. • F/INJR
    • ENG EMIS
    • OXY SEN

Does the test lamp illuminate?

Go to Step 6

Go to Step 11

6

Inspect for poor terminal contact at the underhood electrical center connector of the ignition relay. 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 7

7

Replace the ignition relay.

Did you complete the replacement?

Go to Step 12

--

8

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

Did you complete the repair?

Go to Step 12

--

9

Repair the high resistance or an open in the ignition 1 voltage circuit of the ignition relay.

Did you complete the repair?

Go to Step 12

--

10

Repair the high resistance or an open in the ground circuit of the ignition relay.

Did you complete the repair?

Go to Step 12

--

11

Repair the high resistance or an open in the load circuit of the ignition relay.

Did you complete the repair?

Go to Step 12

--

12
  1. Remove all test equipment.
  2. Connect any disconnected components, fuses, etc.
  3. Turn OFF the ignition for 30 seconds.
  4. Start the engine and operate the vehicle.
  5. Observe the MIL, vehicle performance, and driveability.

Does the vehicle operate normally, with no MIL illumination and no stored DTCs?

System OK

Go to Diagnostic Trouble Code (DTC) List