MAP Sensor Circuit Intermittent High Voltage (Dual Signal) (GM)
What does P1108 mean?
The P1108 code means the vehicle's onboard diagnostic system has detected: MAP Sensor Circuit Intermittent High Voltage (Dual Signal) (GM). This is a moderate severity code.
Common Symptoms
- Check Engine Light on
- Engine running rich
- Rough idle or misfiring
- Decreased fuel economy
- Hesitation under acceleration
Probable Causes (Ranked by Likelihood)
- Defective MAP sensor Very High
- Wiring harness damage near MAP sensor High
- Corroded MAP sensor connector pins Moderate
- Vacuum hose leak or restriction to MAP sensor Moderate
- ECM/PCM malfunction Low
Step-by-Step Diagnostic Procedure
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Read freeze frame data to determine when the fault occurs
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Compare MAP sensor readings with a known-good barometric pressure reading
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Inspect all MAP sensor wiring for chafing, breaks, or shorts
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Check the vacuum hose from the intake manifold to the MAP sensor
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Replace the MAP sensor if electrical and vacuum tests pass but the code persists
Frequently Asked Questions
What is the difference between P1106 and P1108?
Both codes relate to intermittent high MAP sensor voltage on GM vehicles. P1108 typically applies to systems with a dual-signal MAP sensor or a secondary barometric pressure function. The diagnostic approach is similar.
Can I clean a MAP sensor?
Yes, you can carefully clean a MAP sensor with electrical contact cleaner. However, if the sensor is failing intermittently, cleaning may only provide a temporary fix and replacement is recommended.
How much does it cost to replace a MAP sensor?
A MAP sensor typically costs $30 to $80 for the part. With labor, expect to pay $80 to $325 total. It is a relatively easy DIY repair on most GM vehicles.