P1160

Code

VOLKSWAGEN P — Powertrain

Manifold Temperature Sensor Circuit Short To Ground

Brand: VOLKSWAGEN

Type: P — Powertrain

Views: UK: 31 EN: 38 RU: 38

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Page language: EN

Causes

Damaged or chafed wiring with insulation compromised and contacting ground
Corroded, bent or pushed-out connector pins at sensor or ECM
Failed manifold/intake air temperature (MAT/IAT) sensor (internal short)
Aftermarket or incorrect replacement sensor with incompatible characteristics
Water ingress or contamination in connector causing short
ECM driver failure (rare)

Symptoms

MIL/CEL illuminated
Cold start or idle irregularities, poor driveability
Reduced fuel economy or incorrect fuel/ignition trimming
Possible hard start or rough running when intake temp compensation is needed
Loss of engine performance or limp behavior if ECM uses failsafe strategy

What to check

Read and record freeze frame and live data (manifold/intake temp reading, related temps, vehicle speed, engine load)
Visually inspect sensor, connector and wiring harness along intake for damage, corrosion or chafing
Unplug sensor and inspect pins for corrosion, bending or pushed-out terminals
With ignition ON (engine OFF) backprobe signal wire at harness — check for expected pull-up voltage from ECM
With ignition OFF, measure resistance between signal wire and chassis ground to check for short to ground
Measure sensor resistance across its terminals at ambient temp and compare to expected range (or verify voltage change when heated/cooled)

Signal parameters

Sensor type: typically NTC thermistor (resistance decreases as temperature rises)
Signal range: approximately 0.5–4.5 V depending on intake temperature (varies by design)
Reference supply: usually supplied from ECM (approx. 5 V reference or internal pull-up)
Typical resistance range (manufacturer-specific): generally in the low kΩ range at ambient — expect significant change with heating/cooling
A short to ground will show near 0 V on the signal line with ignition ON (engine OFF) or near 0 Ω to chassis ground with meter

Diagnostic algorithm

Verify DTC and related codes. Note freeze-frame and live sensor values.
Perform a careful visual inspection of the sensor, connector, and wiring route for damage, rubbing, or contamination.
With ignition OFF, disconnect the sensor. Measure resistance between the signal wire (harness side) and chassis ground. A low resistance (~0 Ω) indicates a short to ground in the harness.
With ignition ON (engine OFF), measure voltage at the harness signal terminal (backprobe). If voltage is near 0 V, suspect short to ground or ECM driver fault. If reference voltage missing, check ECM output.
Measure sensor resistance at ambient and while heating/cooling the sensor (heat gently with a heat gun or use ice). Confirm resistance changes smoothly — no change or near-zero resistance indicates a failed sensor.
If wiring checks suspect, unplug connectors along the circuit and test continuity from sensor connector to ECM pin. Repair any shorted or damaged sections (repair, replace wiring, or replace connector).
After repairs, clear codes and perform a road or temperature test to verify sensor readings return to normal and DTC does not recur.
If wiring and sensor test good but fault persists, test/replace ECM only after confirming all harness and sensor tests to avoid unnecessary ECM replacement.

Likely causes

Broken insulation on signal wire where it contacts engine/body metal
Sensor connector terminal pushed out and touching ground
Sensor element internally shorted (thermal sensor failure)
Connector corrosion from moisture or oil contamination

Fault status

⚠️ Status

Manifold/intake air temperature sensor circuit indicates a short to ground. ECM detects abnormally low signal voltage or near-zero resistance to chassis ground; fault stored and MIL activated.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 0.5-2.0 hours

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P1160 — Manifold Temperature Sensor Circuit Short To Ground