Code
P1107
GWM
P — Powertrain
- Low Intake Manifold Absolute Pressure (MAP) Sensor Circuit
AI status
Completed
Completed
100%
Causes
- Damaged wiring harness to MAP sensor (open or short to ground)
- Corroded/poor connector at MAP sensor
- Failed MAP sensor (internal fault)
- Blown or poor reference voltage or ground to sensor
- Vacuum leak or physical damage to intake affecting sensor reading
- Faulty PCM (less common)
Symptoms
- Check Engine Light (MIL) illuminated
- Poor idle or rough running
- Reduced power or acceleration
- Driveability issues (hesitation, stalling)
- Lower fuel economy
- Possible hard start in cold conditions
What to check
- Retrieve freeze frame and live data with a scan tool; confirm P1107 is current and note operating conditions
- Visually inspect MAP sensor, connector and wiring for damage, corrosion, pin push-out and signs of water/heat damage
- Backprobe sensor connector with key ON to check reference voltage and ground presence
- Compare live MAP sensor reading to expected values at key ON (engine off), idle and wide open throttle
- Wiggle test wiring while monitoring live data to look for intermittent changes
- Use a handheld vacuum pump (if applicable) to apply vacuum while observing signal change
Signal parameters
- Reference supply: typically ~5.0 V (key ON) to sensor reference pin (vehicle specific)
- Sensor ground: near 0 V with good chassis/PCM ground
- Signal output: typically ~0.5–4.5 V proportional to absolute manifold pressure (low voltage = high vacuum/low pressure, high voltage = high pressure)
- Examples: at high vacuum (idle) signal often ~0.5–2.0 V; at atmospheric/open throttle ~3.5–4.5 V — compare to vehicle-specific data
Diagnostic algorithm
- Confirm code and obtain freeze frame/live data with scan tool; note engine conditions when the code set
- Visually inspect MAP sensor and connector for damage, corrosion, dirt or oil; repair or clean as needed
- With key ON (engine off) backprobe the sensor: verify reference voltage (≈5 V) and good ground; if reference or ground missing, trace and repair wiring to PCM
- Measure signal voltage at sensor with key ON and with engine running; verify signal moves logically with engine vacuum and throttle (apply vacuum with handheld pump if available)
- If signal is stuck low (near 0 V): check for short to ground on signal wire by disconnecting sensor and measuring continuity between signal wire and ground; if short present, repair wiring
- If reference voltage is low or absent: check supply fuse/relay and continuity to PCM; repair as needed
- Perform continuity and resistance checks between MAP connector pins and PCM pins to locate opens or high resistance connections
- If wiring/connector are OK and sensor signal remains incorrect, replace MAP sensor with a known-good unit and re-test
- Clear codes and perform road test; re-scan to confirm code does not return. If problem persists after wiring and sensor replacement, consider PCM diagnosis by a specialist
Likely causes
- Open or shorted signal wire between MAP sensor and PCM
- Corroded/loose connector at MAP sensor
- Failed MAP sensor
- Damaged ground or lost reference voltage
Fault status
Status
P1107 — MAP sensor circuit low/voltage below expected (possible short to ground, open circuit, or failed sensor).
Repair difficulty: Medium
Diagnostic time: 0.5-2 hours
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