Secondary Air Injection Sensor 1, Checking

Special Tools And Workshop Equipment Required 

• Multimeter.
• Wiring diagram.

Test requirements

• The Motronic Engine Control Module (ECM) - J623- fuses OK.
• Battery voltage at least 12.5 volts.
• All electrical consumers such as, lights and rear window defroster, switched off.
• Vehicles with automatic transmission, shift selector lever into position "P" or "N".
• A/C switched off.
• Ground (GND) connections between engine/transmission/chassis OK.
• Ignition switched off.

Test procedure

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

Start diagnosis

-- Remove the engine cover with air filter. Refer to appropriate service information.

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

-- Switch the ignition on.

-- Using a Multimeter, Check the Secondary Air Injection Sensor 1 -G609- electrical harness connector terminals 1 to 3 for voltage.

Specified value: about 5.0 V

-- Switch the ignition off.

If the specification was not obtained:

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-. Refer to appropriate service information.

-- Using a Multimeter, check the Secondary Air Injection Sensor 1 -G609- electrical harness connector to the Motronic Engine Control Module (ECM) -J623- electrical harness connector T105 for resistance.

Secondary Air Injection Sensor 1 -G609- electrical harness connector terminals	Motronic Engine Control Module (ECM) -J623- electrical harness connector T105 terminals
1	20
2	104
3	97

Specified value: 1.5 Ω Max.

If the specified value was not obtained:

-- Check the wiring connection for an open circuit, short circuit to Battery (+) or Ground (GND).

-- Check the wiring connection for damage, corrosion, loose or broken terminals.

-- If necessary, repair the faulty wiring connection.

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

-- Replace Secondary Air Injection Sensor 1 -G609-. Refer to appropriate service information.

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

-- Replace the Motronic Engine Control Module (ECM) -J623-. Refer to appropriate service information.

Assembly is performed in the reverse order of the removal, note the following:

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 .
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 .