Damaged or chafed knock sensor 2 signal wire shorting to ground against the engine block or exhaust shield; Failed knock sensor 2 internally shorted to its housing or ground; Corroded, loose, or water-intruded connector at the knock sensor 2; Wiring harness damage from heat, rodents, or previous repairs near the sensor; Faulty ECM driver circuit for knock sensor 2 (rare but possible); Poor engine ground connection causing a false short-to-ground reading

DTC codes / Volkswagen codes / P1320

P1320 · VolkswagenKnock Sensor 2 Circuit Short To Ground

Q: What does code P1320 mean?

Knock Sensor 2 Circuit Short To Ground. P1320 on Volkswagen vehicles indicates that the engine control module (ECM) has detected a short to ground on the signal circuit for Knock Sensor 2, which is typically located on the right bank of a V6 or V8 engine. The ECM monitors the sensor's output and expects a specific voltage range; a constant ground-level signal triggers this fault, disabling the sensor's ability to detect engine knock and forcing the ECM to rely on conservative ignition timing.

P1320 on Volkswagen vehicles indicates that the engine control module (ECM) has detected a short to ground on the signal circuit for Knock Sensor 2, which is typically located on the right bank of a V6 or V8 engine. The ECM monitors the sensor's output and expects a specific voltage range; a constant ground-level signal triggers this fault, disabling the sensor's ability to detect engine knock and forcing the ECM to rely on conservative ignition timing.

SystemPowertrain

Code typeVolkswagen specific

SeverityMedium

Fix difficultyIntermediate

AreaIgnition system and misfire

Symptoms you may notice

Illuminated check engine light, often with no other noticeable symptoms
Reduced engine power and sluggish acceleration due to retarded ignition timing
Decreased fuel economy as the ECM enriches the mixture to protect the engine
Occasional engine knocking or pinging under load if the ECM cannot retard timing enough
Rough idle or hesitation in some cases, especially if the short affects shared sensor wiring

Common causes, most likely first

Damaged or chafed knock sensor 2 signal wire shorting to ground against the engine block or exhaust shield
Failed knock sensor 2 internally shorted to its housing or ground
Corroded, loose, or water-intruded connector at the knock sensor 2
Wiring harness damage from heat, rodents, or previous repairs near the sensor
Faulty ECM driver circuit for knock sensor 2 (rare but possible)
Poor engine ground connection causing a false short-to-ground reading

How to diagnose and fix it

Scan all modules for stored codes and freeze-frame data to confirm P1320 is the only knock-related fault
Visually inspect the knock sensor 2 and its wiring for obvious damage, corrosion, or loose connections
Disconnect the sensor and measure resistance from the signal terminal to ground; a near-zero reading indicates a shorted sensor or harness
Isolate the harness by disconnecting the ECM and checking for continuity to ground on the signal wire; repair any chafed or pinched sections
Replace the knock sensor 2 if it fails resistance or continuity tests, and clear codes to verify the fix
Check and clean engine ground straps and battery terminals to rule out ground-related false shorts
If the wiring and sensor test good, perform a wiggle test on the harness while monitoring live data for knock sensor voltage to catch intermittent shorts

Knock sensor 2 short-to-ground pitfalls

A common mistake is replacing the knock sensor when the real problem is a chafed signal wire shorting against the engine block or a heat shield, so always inspect the harness before condemning the sensor.
Volkswagen's knock sensor circuits are sensitive to poor engine grounds; a corroded ground strap can cause a false short-to-ground code even when the sensor and wiring are intact.
P1320 can be set intermittently by water intrusion into the sensor connector after engine washing or heavy rain, so check for moisture and corrosion inside the plug.
On some VW engines, the knock sensor 2 shares a ground path with other sensors, and a short in a neighboring circuit can mimic a knock sensor fault, so review all codes before diagnosing.
The ECM may not illuminate the check engine light immediately for a knock sensor short; the code can be stored pending without the driver noticing any performance change.

Can I keep driving with P1320?

You can usually drive the vehicle with P1320 set, but avoid heavy acceleration and towing because the ECM may not be able to retard ignition timing properly, increasing the risk of engine knock and potential damage. Have the fault diagnosed soon to restore full engine protection and performance.

Tools that help

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Guidance is general and written for Volkswagen vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.