P0107 – MAP/barometric pressure circuit input low

Last updated: March 29, 2026

DTC P0107 is an ISO/SAE controlled powertrain code that indicates a circuit fault: the engine control module (ECM/PCM) is detecting a MAP/barometric pressure circuit input low. This is an electrical interpretation of the sensor signal—meaning the module is seeing a voltage input that is lower than expected—rather than a guaranteed diagnosis of a failed sensor. Because the MAP/barometric pressure signal is used to calculate engine load, a low circuit input can cause the ECM to use inaccurate load information, which may affect fueling, ignition timing, and overall drivability. Proper diagnosis focuses on verifying the 5-volt reference, sensor ground, signal integrity, and connector condition before replacing any components.

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P0107 Quick Answer

P0107 – MAP/barometric pressure circuit input low means the ECM/PCM is seeing an abnormally low voltage on the MAP/barometric pressure signal circuit. Prioritize checks of the MAP sensor connector, the 5-volt reference supply, sensor ground quality, and the signal wire for opens or shorts to ground.

What Does P0107 Mean?

P0107 means MAP/barometric pressure circuit input low. In other words, the ECM/PCM has determined that the electrical input from the MAP/barometric pressure circuit is below the expected operating range for the current conditions.

This is a circuit code: it does not automatically mean the engine is truly experiencing an unusually low pressure event. Instead, it indicates the control module is receiving a low electrical signal (typically low voltage) from the MAP/barometric pressure circuit, which can be caused by wiring, connector, power/ground, or the sensor itself. The result is that the module may not be able to rely on the MAP/barometric pressure input for accurate calculations.

Theory of Operation

The MAP sensor converts pressure information into a voltage signal that the ECM/PCM can interpret. The module typically provides a regulated reference voltage (often 5 volts), a sensor ground, and reads a return signal voltage on the signal circuit. With key on/engine off, the MAP sensor value generally corresponds to barometric pressure because manifold pressure is close to ambient with no engine vacuum.

P0107 sets when the ECM/PCM detects that the MAP/barometric pressure signal circuit input is too low compared with what it expects. A short to ground on the signal wire can pull the voltage down immediately. Excessive resistance in the reference or ground circuit can also reduce the sensor’s usable output and make the module interpret the circuit input as low, even if the sensor itself is capable of producing the correct signal under proper electrical conditions.

Symptoms

• Check Engine Light (MIL) illuminated
• Hesitation or stumble during throttle changes
• Rough, unstable, or hunting idle
• Reduced engine power or poor acceleration response
• Possible stalling, especially during deceleration or when coming to a stop
• Fuel economy changes due to incorrect engine load calculation

Common Causes

• MAP/barometric pressure signal circuit shorted to ground
• Open circuit or high resistance in the MAP/barometric pressure signal wire
• Low or missing reference voltage supply to the MAP sensor circuit
• High resistance, poor connection, or voltage drop on the MAP sensor ground circuit
• Connector issues at the MAP sensor (corrosion, moisture intrusion, terminal damage, poor pin tension)
• MAP sensor internal electrical fault producing a low circuit output
• ECM/PCM input circuit issue (less common, considered after external circuit testing)

Diagnosis Steps

Tools needed: Scan tool with live data and freeze-frame access, DVOM (digital volt/ohm meter), back-probing tools, wiring diagram for the exact vehicle/engine, and basic hand tools for connector and harness inspection. If applicable to the design, a vacuum pump can be used to observe sensor response, but the focus for P0107 remains verifying the electrical circuit input low condition.

1. Confirm the code and capture data: Verify P0107 is present (pending or confirmed). Record freeze-frame information, including RPM, load, battery voltage, and the MAP/barometric pressure reading when the fault was detected.
2. Clear and recheck for an immediate return: Clear the DTC and cycle the key. If P0107 returns immediately, treat it as a likely hard electrical fault (such as a short to ground, missing reference voltage, or failed ground).
3. Perform a detailed visual inspection: Inspect the MAP sensor connector for water intrusion, corrosion, damaged seals, bent pins, pushed-out terminals, and broken connector locks. Inspect the harness routing for rubbing, pinching, or contact with hot/sharp surfaces.
4. Check power supply basics: Verify ECM/PCM and sensor supply fuses and power feeds are present and stable. Do not rely on visual fuse inspection only; confirm voltage where appropriate.
5. Verify reference voltage at the sensor connector: With the connector back-probed (key on, engine off), measure the reference voltage at the MAP sensor reference terminal. If the reference is low or missing, diagnose the reference circuit and any shared reference loads per the wiring diagram.
6. Verify sensor ground integrity with a voltage-drop approach: Test the sensor ground circuit for unwanted voltage drop. A ground circuit can show continuity and still fail under operating conditions due to resistance at a splice, terminal, or ground point.
7. Measure the MAP/barometric pressure signal voltage: With the sensor connected, measure the signal circuit voltage and compare it to the scan tool PID behavior. A signal that is consistently near 0 volts supports a circuit input low condition.
8. Unplug the MAP sensor and observe the signal behavior: Disconnect the sensor and recheck the scan PID and/or signal voltage. If the signal remains low with the sensor unplugged, suspect a signal wire short to ground or an ECM/PCM input-side issue. If the signal changes when unplugged, the sensor or connector becomes more suspect (after confirming reference and ground are correct).
9. Check the signal circuit for shorts to ground and opens: With the circuit safely isolated per service information, test for unintended continuity to ground on the signal wire and verify continuity end-to-end where applicable. Wiggle the harness during testing to identify intermittent faults.
10. Verify repair and confirm the fix: After repairs, clear codes and road test under varied operating conditions while monitoring the MAP/barometric pressure PID for stable, reasonable behavior. Confirm P0107 does not return and that readiness/monitors complete as applicable.

Professional tip: When P0107 resets immediately after clearing (especially key on/engine off), focus first on proving the reference voltage, sensor ground, and signal wire are electrically correct. A true “circuit input low” is often identified fastest with direct voltage measurements and voltage-drop testing rather than relying on resistance checks alone.

Possible Fixes

• Repair a short to ground on the MAP/barometric pressure signal circuit
• Repair an open or high-resistance condition in the MAP/barometric pressure signal wire
• Restore proper reference voltage supply to the MAP sensor circuit (repair wiring, connection, or related feed issue as applicable)
• Repair high resistance or poor connection on the MAP sensor ground circuit
• Clean, repair, or replace damaged connector terminals and ensure proper pin tension and sealing
• Replace the MAP sensor only after confirming reference voltage, ground integrity, and signal circuit behavior
• Address an ECM/PCM input circuit concern only after all external circuit tests confirm correct wiring and connections

Can I Still Drive With P0107?

Driving with P0107 may be possible in some situations, but it is not advisable to ignore it because the ECM/PCM is reporting a MAP/barometric pressure circuit input low condition that can affect engine load calculations. If drivability is unstable (stalling, severe hesitation, or loss of power), reduce driving and diagnose promptly. If the engine runs relatively smoothly, limit driving to what is necessary to reach a safe location for testing and repair, and avoid heavy load operation that could worsen performance issues created by inaccurate load input.

How Serious Is This Code?

P0107 can range from moderate to severe depending on how the ECM/PCM reacts to the low circuit input and how heavily the strategy depends on MAP/barometric pressure information. Because it indicates an electrical input problem, it can be intermittent or constant, and either condition can lead to incorrect engine calculations. In more disruptive cases, the vehicle may experience poor drivability or stalling. The seriousness increases when the low input is constant, when the code returns immediately after clearing, or when the vehicle exhibits unstable operation that could affect safe driving.

Common Misdiagnoses

The most frequent misdiagnosis with P0107 is replacing the MAP sensor without verifying the circuit. Because the official meaning is MAP/barometric pressure circuit input low, the diagnostic priority should be confirming the reference voltage supply, sensor ground integrity, and signal wire condition (including shorts to ground and opens). Skipping connector inspection can also lead to missed terminal damage or moisture intrusion that lowers the circuit input. Another error is assuming continuity checks alone prove a circuit is good; a circuit can pass an ohms test and still fail under load due to voltage drop at terminals or splices.

Most Likely Fix

The most likely fix for P0107 is correcting the circuit condition causing the MAP/barometric pressure input to read low—most often by repairing wiring or connector issues affecting the signal circuit, reference voltage, or sensor ground. Once proper power, ground, and signal integrity are verified, replacing the MAP sensor becomes appropriate only if the circuit is proven good yet the input remains low.

Repair Costs

Repair cost depends on whether the confirmed root cause is a sensor, wiring, connector issue, or control module problem. Verify the fault electrically before replacing parts.