Knock Sensor 1, Checking

The following procedure is used to diagnose all Knock Sensors --.

Special tools and workshop equipment required 

• Multimeter.
• Wiring diagram.

Test requirements 

• The mounting bolt of Knock Sensor (KS) 1 -G61- /Knock Sensor (KS) 2 -G66- tightened to 20 Nm.
• The 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 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 the Repair information.

-- Disconnect the Knock Sensor (KS) 1 -G61- electrical harness connector -1-

Fig 1: Electrical Harness Connectors

Courtesy of AUDI OF AMERICA, LLC

Checking internal resistance 

-- Using a multimeter, check the Knock Sensor terminals 2 to 3 for an internal short.

Fig 2: Checking Knock Sensor (KS) 1 -G61- Terminals 1 To 2 For An Internal Short

Courtesy of AUDI OF AMERICA, LLC

Specified value: OL or (Infinity).

-- Using a multimeter, check the Knock Sensor terminals 1 to 2 for resistance.

Specified value: 5 MΩ (+/- 1 MΩ).

If any of the specified values were Not obtained:

-- Replace the faulty Knock Sensor (KS) 1 -G61-. Refer to the Repair information.

If the specified values were obtained:

Checking wiring 

-- Remove the Engine Control Module (ECM) -J623-. Refer to the Repair information.

-- Using a multimeter, Check the Knock Sensor electrical harness connector to the Engine Control Module (ECM)J623 electrical harness connector T60 for an open circuit.

Fig 3: Identifying 3-Pin Connector

Courtesy of AUDI OF AMERICA, LLC

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 positive or Ground.

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

-- If necessary, repair the faulty wiring connection.

If no malfunction is found in wiring and the sensor resistance checks were OK:

-- Replace the Engine Control Module (ECM) -J623-. Refer to the Repair information.

-- Install the engine cover. Refer to the Repair information.

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 .