P1322–P1324 Knock Sensor 3 (G198) Circuit: High Input

Which code is which

Same fault, different cylinder or bank — diagnosed the same way. Several set together usually means one shared cause.

The definition

P1322: Knock Sensor 3 (G198) Circuit: High Input.

P1322 is a manufacturer-specific powertrain code (the engine or gearbox). Its meaning is set by the carmaker rather than by the SAE standard, so a generic OBD-II reader will often show it as an unknown code or misread it.

What to check first

Cheapest and fastest checks first:

1. Unplug the sensor and check whether the signal falls. If it stays high, suspect the wiring rather than the sensor.
2. Check the earth path - a missing earth makes a sensor read high.

What actually causes this on a VAG

G198 is knock sensor 3, and it only exists on engines carrying three or more knock sensors - in the VAG range the big multi-cylinder units such as the V8s, V10s and W12s, normally with two sensors per bank. "High input" is the opposite pattern to a short: the ECU is seeing the circuit read above anything plausible, which almost always means an open circuit - a connector not plugged in properly, a broken wire, a pin pushed back in its housing, or a sensor gone open internally. The ECU responds by retarding ignition on that bank, so the car feels slightly flat and uses a little more fuel, but nothing is being harmed.

Most likely causes, in order

1. Connector not fully latched or left unplugged. Far and away the most common cause, and it is usually obvious in the history: the code appears right after a cambelt, an intake manifold off, a coolant pipe in the vee, or a starter motor. Find the plug, unlatch it, look at the pins, and push it back until it clicks properly home. A plug that is pushed on but not latched will work loose again with engine vibration and give you an intermittent fault that comes back weeks later.
2. Broken wire or pushed-back pin. An open circuit anywhere between the sensor and the ECU sets this code. Look where the loom is pulled tight over brackets or studs, or where it could have been nipped as the manifold was refitted, and check inside the connector body for a terminal that has been pushed back and no longer meets its partner. A gentle tug on each individual wire at the back of the plug will find it. Then prove it properly: continuity from each pin in the sensor plug back to its pin at the ECU connector.
3. Sensor open internally. The sensor's internal lead can fracture, which reads as an open circuit. Be aware you cannot prove a knock sensor good or bad with an ohmmeter across its two pins - a piezo sensor reads near enough infinite either way, so a meter tells you nothing there. That is exactly why the loom has to be proven first: this is the answer once the plug and the wiring are known good, not before.

Worth knowing: If this code appeared straight after engine work, treat it as a workshop error until proven otherwise and go back to whatever was disturbed - a plug half-latched, a plug left hanging, or a loom nipped as the manifold went back down. Do not order a sensor on the strength of the code alone: on these engines the sensor is buried under the intake manifold, so an unlatched plug and a failed sensor cost roughly the same to reach but wildly different amounts to fix, and the plug is free.

Common questions

What does P1322 mean?

P1322 means Knock Sensor 3 (G198) Circuit: High Input. The voltage on this circuit is sitting near battery voltage. Typically a short to a positive feed, or a disconnected sensor floating high.

Can I drive with P1322?

This class of fault can cause real mechanical damage if you keep driving on it. A persistent misfire also destroys the catalytic converter, which is the expensive part.

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