P1161

Code

VOLKSWAGEN P — Powertrain

Manifold Temperature Sensor Circuit Open/Short To B+

Brand: VOLKSWAGEN

Type: P — Powertrain

Views: UK: 47 EN: 93 RU: 64

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Page language: EN

Causes

Open or shorted wiring between manifold temperature sensor and ECM
Corroded, loose or damaged sensor connector/pins
Failed manifold temperature (intake air temp) sensor (thermistor)
Short to B+ caused by pin pushed into connector or chafed insulation contacting power
Poor or missing ground at sensor/ECM grounds
ECM internal fault (rare) or recent incorrect wiring after repairs

Symptoms

Check Engine Light (MIL) illuminated
Engine may run using default/backup temperature values (possible rough idle or poor cold running)
Reduced fuel economy or increased emissions
Hard starting in some conditions
Stored DTC P1161 in fault memory; freeze frame data may show abnormal sensor voltage

What to check

Read stored codes and freeze frame data with a scan tool; record live manifold temperature sensor values
Visually inspect sensor connector, wiring harness and nearby components for damage, heat or corrosion
Backprobe sensor connector with key ON (engine OFF) and measure signal voltage; compare to expected range
Measure resistance of the sensor (thermistor) at ambient temperature and while heated/cooled (ice water / warm water)
Check for continuity between sensor signal pin and ECM pin; check for short to battery positive and to ground
Wiggle harness and connectors while monitoring live data to reproduce intermittent faults

Signal parameters

Sensor type: usually NTC thermistor (resistance decreases as temperature rises)
Typical sensor resistance at 25°C: roughly 1–10 kΩ depending on design (consult factory data for exact values)
Signal voltage range: 0.1–4.9 V (varies by model and ECU). A short to B+ commonly shows high voltage near battery voltage reference; an open may show no/very low voltage or out-of-range value
Expected trend in live data: temperature reading should change smoothly with actual manifold air temperature

Diagnostic algorithm

Verify the code and note freeze frame/live data (manifold temperature reading and related parameters).
Visually inspect the manifold temp sensor, connector and harness for damage, corrosion, heat, or oil contamination.
With key ON (engine OFF) backprobe the signal and reference pins. Check reference voltage (if present) and sensor output voltage. Compare to expected range.
Disconnect sensor and measure sensor resistance at ambient. Then change sensor temperature (ice/warm water) to verify resistance changes appropriately. Replace sensor if out of spec or open/short.
Check continuity between sensor connector pin and ECM harness pin. Measure for shorts to battery positive and to ground (infinite or high resistance expected to non-related circuits).
Repair any damaged wiring or connector faults (replace pins, repair harness, protect routing). After repair clear codes and re-test.
If wiring and sensor test good but code returns, perform ECM input pin testing per factory procedures or consider ECM replacement only after confirming other causes eliminated.

Likely causes

Damaged connector or corroded pins at the manifold temperature sensor
Broken or chafed wire shorting to battery positive in harness near the intake
Failed manifold temperature sensor (open or internal short)
Pin pushed out of connector causing intermittent short to B+
Less likely: ECM input circuit failure

Fault status

⚠️ Status

Manifold Temperature Sensor Circuit Open or Short to B+. ECM detects invalid or out-of-range manifold air temperature signal, stored fault P1161; MIL may be illuminated and default values used for control.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 0.5-2 hours

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P1161 — Manifold Temperature Sensor Circuit Open/Short To B+