Air Injection Pump Relay: Testing and Inspection

Diagnostic Procedures



Secondary Air Injection Pump Relay, Checking

Special tools, testers and auxiliary items required

• Multimeter.

• Wiring diagram.

Test requirements

• Fuse (S130) OK.

• The Engine Component Power Supply Relay (J757) 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 2/30 to Ground (GND).

Specified value: battery voltage.

If the specified value was not obtained:

- Check the wiring connection from the battery to the Secondary Air Injection (AIR) Pump Relay (-J299-) socket 2/30 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:

- Crank the engine.

- Using a Multimeter, check the Secondary Air Injection (AIR) Pump Relay (-J299-) socket 6/86 to Ground (GND).

Specified value: battery voltage.

- Switch the ignition off.

If the specified value was not obtained:

- Check the wiring connection from the Engine Component Power Supply Relay (J757) socket 2/87 to the Secondary Air Injection (AIR) Pump Relay (-J299-) socket 6/86 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 Repair Manual (test box) at Engine Control Module.

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

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

- Using a Multimeter, check the Secondary Air Injection (AIR) Pump Relay (-J299-) socket 4/85 to the Motronic Engine Control Module (ECM) (J623) electrical harness connector T94a terminal 49 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).

- Assembly is performed in the reverse order of removal.

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 Modes 01 - 09.

2. If necessary, erase the DTC memory. Refer to => [ Diagnostic Mode 04 - Erase DTC Memory ] Diagnostic Modes 01 - 09.

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

- End of diagnosis.