Combination Valve For Secondary Air Injection (AIR), Checking Function and Proper Seal

Secondary Air Injection (AIR) Pump Relay -J299-, 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 necessary, repair the faulty wiring connection.

Checking wiring
If the manufacturers test box is being used. Perform the following step.
- Install the test box.

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 85 to the Motronic Engine Control Module (ECM) J623 electrical harness connector T121 terminal 46 for resistance.

Motronic Engine Control Motronic Engine Control
Module (ECM) Power Supply Module (ECM) J623 electrical
Relay J271 socket terminal connector T121 terminal or test box socket
85 46

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. Diagnostic Mode 03 - Read DTC Memory
2. If necessary, erase the DTC memory. Diagnostic Mode 04 - Erase DTC Memory
3. If the DTC memory was erased, generate readiness code.

- End of diagnosis.