What Does P1103 Mean?
P1103 indicates the Manifold Absolute Pressure (MAP) sensor is outputting a voltage higher than the expected range. This typically means the ECM is seeing a signal that suggests an unrealistically high manifold vacuum or a shorted sensor circuit. The engine may run rich, surge, or exhibit poor fuel economy due to incorrect load calculations based on erroneous MAP data.
Common Causes
35%
Faulty MAP sensor with internal short to voltage
25%
Wiring issue — short to power in the MAP signal circuit
20%
Vacuum hose disconnected or cracked at MAP sensor port
12%
Corroded or damaged MAP sensor connector pins
8%
ECM internal fault on MAP input circuit
Diagnostic Steps
1
Step 1: Monitor MAP sensor voltage with key on, engine off (KOEO). Normal reading should be approximately 4.0–4.7V (atmospheric pressure). If already pegged at 5V, suspect a short to power.
2
Step 2: Start the engine and observe MAP voltage at idle. It should drop to approximately 1.0–2.0V depending on engine load. A reading that stays above 4V indicates a sensor or circuit fault.
3
Step 3: Disconnect the MAP sensor and check for 5V reference and good ground at the connector. If reference and ground are correct, the sensor itself is likely faulty.
4
Step 4: Inspect the vacuum hose to the MAP sensor for cracks, splits, or disconnection. A missing or leaking hose will cause incorrect pressure readings.
5
Step 5: With the sensor disconnected, check the signal wire for shorts to battery voltage or the 5V reference wire using a multimeter. Repair any wiring faults found.
6
Step 6: If wiring and vacuum supply check out, replace the MAP sensor. Clear codes and verify the reading normalizes across idle and load conditions.
Estimated Repair Cost
$50 - $250
Parts + labor, varies by vehicle and location
P1103 indicates the Manifold Absolute Pressure (MAP) sensor is outputting a voltage higher than the expected range. This typically means the ECM is seeing a signal that suggests an unrealistically high manifold vacuum or a shorted sensor circuit. The engine may run rich, surge, or exhibit poor fuel ...
The most common cause of P1103 (Manifold Absolute Pressure (MAP) Sensor Malfunction - High Voltage) is: Faulty MAP sensor with internal short to voltage
Typical repair costs for P1103 range from $50 to $250, depending on the vehicle, location, and whether you do it yourself or go to a shop.
A faulty MAP sensor can cause incorrect air/fuel ratios leading to rough running, stalling, or hesitation during acceleration, which could be dangerous during highway merging or passing maneuvers.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P1103 to identify the root cause.
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Quick Info
Category
Powertrain
System
Engine Management / Fuel Delivery
Difficulty
Type
Manufacturer
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