What does it mean?
P1332 is a Powertrain (engine, transmission, fuel system) fault code. It indicates: Knock Sensor 4 Signal Low Input .
Symptoms
- Check engine light on with the fault stored for the second bank
- Flat performance and lazy pickup, because timing is pulled back without knock feedback
- Fuel consumption creeps up on the same route
- Detonation rattle under heavy load, especially with lower octane fuel or in high ambient temperature
- Power delivery can feel uneven between the two banks
Likely causes
- Sensor 4 loose on the block, or corrosion and paint between the sensor foot and the mounting surface
- Break or high resistance in the signal or return wire on the way to the module
- Water or oil sitting in the connector, which is common on sensors mounted low in the vee
- Damaged shield around the sensor pair, so the module only sees a weak level
- Piezo element inside knock sensor 4 has failed and no longer produces output
- Chafed harness where it passes a bracket or a coolant pipe under the manifold
- Module knock input failure, which is uncommon and only considered last
How to fix it
- Note the conditions in the freeze frame, then verify whether the code returns immediately or only after a load test
- Gain access to the sensor, which often means removing the intake manifold, and inspect the connector for corrosion and moisture
- Measure the resistance of knock sensor 4 and compare it with the sensor on the same bank if the engine has one
- Check the signal wire and shield continuity from the connector to the module pin, and wiggle-test the harness while watching for a dropout
- Clean the mounting boss, install the sensor without any washer that does not belong there, and torque it to the exact specification
- Retest with live data while tapping the block near the sensor to confirm the channel responds
- Replace the sensor if the response is still absent; check module pin condition before condemning the module