Secondary Air Injection Sensor, Checking

Special tools and workshop equipment required 

• multimeter.
• Wiring diagram.

Test requirements 

• Fuse -SB10- OK.
• The Motronic Engine Control Module (ECM) Power Supply Relay -J271- OK.
• The ignition switched off.

Test procedure 

-- Perform a preliminary check to verify the customers complaint. Refer to PRELIMINARY CHECK .

Start diagnosis 

-- Disconnect the Secondary Air Injection Sensor 1 -G609- electrical harness connector -1-.

Checking voltage supply 

-- Using a multimeter, check the Secondary Air Injection Sensor 1 -G609- electrical harness connector terminal 4 for voltage.

Secondary Air Injection Sensor 1 -G609- electrical harness connector terminal	Measure to
-4-	Engine Ground (GND)

-- Operate the engine briefly.

Specified value: approx. 5 V.

-- Switch the ignition off.

If the specified value was not obtained:

-- Using a multimeter, check the Secondary Air Injection Sensor 1 -G609- electrical harness connector terminal 4 to the Motronic Engine Control Module (ECM) -J220- terminal 53 for resistance.

Specified value: 1.5 Ω max

If the specification was not obtained:

-- Check the wiring for a short circuit to Battery positive (+) or an open circuit.

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

-- If necessary, repair the faulty wiring connection.

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

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 Engine Control Module (ECM) -J220-. Refer to appropriate service information.

-- Using a multimeter, check the Secondary Air Injection Sensor 1 -G609- electrical harness connector terminals to Engine Control Module (ECM) -J220- electrical harness connector T121 terminals.

Secondary Air Injection Sensor 1 -G609- electrical harness connector terminals	Engine Control Module (ECM) -J220- electrical connector T121 terminals or test box sockets
1	50
3	74
4	53

Specified value: 1.5 Ω max.

If the specification is not obtained:

-- Check the wiring for a short circuit to Battery positive (+), or an open circuit.

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

-- If necessary, repair the faulty wiring connection.

If no malfunction is found in wiring:

-- Erase the DTC memory. Refer to DIAGNOSTIC MODE 04 - ERASE DTC MEMORY .

-- Perform a road test to verify repair.

If the DTC does not return:

Generate readiness code. Refer to READINESS CODE .

If the DTC does return and no malfunction is detected in the wiring and the voltage supply was OK:

-- Replace the Engine Control Module (ECM) -J220-. Refer to appropriate service information.

-- Assembly is performed in the reverse of the removal.

Final procedures 

After the 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 .
2. If necessary, erase the DTC memory. Refer to DIAGNOSTIC MODE 04 - ERASE DTC MEMORY .
3. If the DTC memory was erased, generate readiness code. Refer to READINESS CODE .