Air Injection Pump Relay: Testing and Inspection

Secondary Air Injection Pump Relay, Checking

Special tools, testers and auxiliary items required

• Multimeter.

• Wiring diagram.

Test requirements

• The Secondary Air Injection (AIR) Pump Fuse (S130 ) OK.

• The Motronic Engine Control Module (ECM) Power Supply Relay (J271) fuse OK.

• Battery voltage at least 12.5 V.

• All electrical consumers switched off (radiator fan must NOT run during test).

• A/C switched off.

• The ignition switched off.

Procedure

- Remove the Secondary Air Injection (AIR) Pump Relay (-J299-).

Checking voltage

- Using a Multimeter, check the Secondary Air Injection (AIR) Pump Relay (-J299-) socket 87 to Ground (GND).

Specified value: battery voltage.

If the specified value was not obtained:

- Check the wiring connections from the Battery to the Secondary Air Injection (AIR) Pump Relay (-J299-) socket 87 for an open circuit or a short circuit.

- Check the wiring connections for damage, corrosion, lose or broken terminals.

- If necessary, repair the faulty wiring connection.

If the specified value was obtained:

- Switch the ignition on.

- Using a Multimeter, check the Motronic Engine Control Module (ECM) Power Supply Relay (J271) socket 87 to the Secondary Air Injection (AIR) Pump Relay (-J299- ) socket 85 for voltage.

- Switch the ignition off.

Specified value: battery voltage.

If the specified value was not obtained:

- Check the wiring connections from the Motronic Engine Control Module (ECM) Power Supply Relay (J271) socket 87 to the Secondary Air Injection (AIR) Pump Relay (-J299-) socket 25 for an open circuit or a short circuit.

- Check the wiring connections for damage, corrosion, lose or broken terminals.

- If necessary, repair the faulty wiring connection.

If the specified value was obtained:

Checking activation

- Switch the ignition on.

- Using a Multimeter, check the Secondary Air Injection (AIR) Pump Relay (-J299-) socket 2/24 to Ground (GND)

- Switch the ignition off.

Specified value: battery voltage.

If the specified value was not obtained:

- Check the wiring connection from the Secondary Air Injection (AIR) Pump Relay (-J299-) socket 85 to the Motronic Engine Control Module (ECM) (J623) electrical harness connector T121 terminal 49 for an open circuit or a short circuit.

- Check the wiring connections for damage, corrosion, lose or broken terminals.

- If necessary, repair the faulty wiring connection.

If the specified value was obtained:

Checking wiring

If the manufacturers test box is being used. Perform the following step.

- Install the test box. Refer to Fuel Injection and Ignition Repair Information.

If the manufacturers test box is not being used. Perform the following step.

- Remove the Motronic Engine Control Module (ECM) ( J623). Refer to => [ Engine Control Module, Replacing ] Service and Repair.

- Using a Multimeter, check the Secondary Air Injection (AIR) Pump Relay (-J299-) socket 85 to the Motronic Engine Control Module (ECM) (J623) electrical harness connector T121 terminal 46 for resistance.





Specified value: 1.5 ohms Max.

If the specification was not obtained:

- Check the wiring for a short circuit to each other, Battery (+), and Ground (GND).

- Check the electrical harness connector for damage, corrosion, lose or broken terminals.

- If necessary, repair the faulty wiring connection.

If no malfunction is found in the wiring and voltage supply was OK:

- Replace the Secondary Air Injection (AIR) Pump Relay (-J299-).

If no malfunction is found in the wiring and voltage supply was not OK:

- Replace the Motronic Engine Control Module (ECM) (J623).

Final procedures

After repair work, the following work steps must be performed in the following sequence:

1. Check the DTC memory. Refer to => [ Diagnostic Mode 03 - Read DTC Memory ] Diagnostic Mode 03 - Read DTC Memory.

2. If necessary, erase the DTC memory. Refer to => [ Diagnostic Mode 04 - Erase DTC Memory ] Diagnostic Mode 04 - Erase DTC Memory.

3. If the DTC memory was erased, generate readiness code. Refer to => [ Readiness Code ] Monitors, Trips, Drive Cycles and Readiness Codes.

- End of diagnosis.