P0107 Code — MAP/Barometric Pressure Circuit Low Input (Causes & How to Fix)
Fix OBD-II code P0107: MAP/Barometric Pressure Circuit Low Input. Step-by-step diagnosis and repair guide.
What Does DTC P0107 Mean?
P0107 on your Powertrain Fuel & Air system means: The engine control module is seeing a voltage that is lower than the minimum it expects from the MAP (Manifold Absolute Pressure) sensor. This usually means the sensor, its wiring, or the sensor’s reference voltage is compromised, causing the PCM to receive inaccurate pressure data.
How to Diagnose and Fix P0107 — Step by Step
- 1
Visual Inspection – Loose Cap, Connector, and Wiring
1. Open the hood and locate the MAP sensor (usually on or near the intake manifold). 2. Verify the gas cap is tightened to the proper torque; a loose cap can create a vacuum leak that fools the MAP sensor. 3. Inspect the sensor’s electrical connector for corrosion, bent pins, or a loose clip. 4. Follow the wiring harness back toward the PCM and look for chafed insulation, cracked clips, or burnt spots. 5. Re‑seat the connector and, if you see any damaged wires, repair or replace them before moving on.
- 2
Live Data Scan – Check MAP Voltage
1. Plug an OBD‑II scanner that can display live data into the vehicle’s diagnostic port. 2. Select the MAP sensor PID (usually labeled “MAP” or “Barometric Pressure”). 3. With the engine at idle (≈750 rpm) and the vehicle at sea‑level pressure, the MAP voltage should sit roughly between 2.0 V and 3.0 V. 4. Compare the live reading to the expected range. If the voltage is consistently below 0.5 V, the circuit is reading “low input.” 5. Note any fluctuations when you gently tap the sensor or wiggle the connector—spikes indicate a loose connection.
- 3
Multimeter Test – Sensor Ground and Reference Voltage
1. Disconnect the MAP sensor connector. 2. Set a digital multimeter to DC voltage. 3. Back‑probe the sensor’s reference wire (usually 5 V) while the ignition is ON. A healthy reference should read close to 5 V (+/‑0.2 V). 4. Switch the meter to continuity mode and place the probes on the sensor ground terminal and chassis ground; you should hear a beep, confirming a solid ground path. 5. If the reference voltage is missing or the ground shows high resistance, the problem lies in the wiring or PCM supply rather than the sensor itself.
- 4
Vacuum Leak Check – Hose and Intake Inspection
1. Locate the vacuum hose that feeds the MAP sensor (often a small rubber tube). 2. With the engine running, listen for hissing sounds using a length of hose or a piece of rubber tubing placed over each connection. 3. Spray a short burst of carburetor cleaner on each hose and the sensor’s mounting surface; a change in idle speed indicates a leak. 4. Replace cracked hoses or reseat the sensor’s mounting flange if you detect a leak. 5. Re‑run the live data scan after the repair to see if the voltage normalizes.
- 5
Sensor Cleaning – Remove Dirt or Carbon Build‑up
1. If visual inspection shows grime on the sensor’s diaphragm, remove the MAP sensor using a 10 mm socket. 2. Gently wipe the diaphragm with a lint‑free cloth and a small amount of electronic‑grade cleaner. 3. Avoid touching the thin membrane with your fingers; any oil can cause false readings. 4. Reinstall the sensor, reconnect the wiring, and re‑check live data. 5. Cleaning often restores a low‑input reading caused by contamination.
- 6
Replace the MAP Sensor
1. When voltage remains low after the previous steps, the sensor itself is likely defective. 2. Purchase a replacement MAP sensor that matches your vehicle’s make, model, and engine (e.g., “MAP sensor for 2015‑2018 Chevrolet Silverado 5.3 L”). 3. Disconnect the battery (negative terminal) to protect the PCM. 4. Remove the old sensor, install the new one, and torque the mounting bolts to the manufacturer’s specification (usually around 8‑10 Nm). 5. Re‑connect the battery, clear the DTC with the scanner, and perform a short test drive.
- 7
Clear Codes and Verify Repair
1. With the OBD‑II scanner, select “Erase Codes” or “Clear DTCs.” 2. Turn the ignition off, wait a few seconds, then restart the engine. 3. Watch the live MAP data for at least two minutes; it should stay within the normal voltage range and not dip low when you accelerate. 4. If the code returns, re‑examine wiring and PCM voltage supply; otherwise, the repair is complete. 5. Take the vehicle on a varied drive (city, highway, idle) to confirm smooth operation.
When to Call a Professional Mechanic
If the MAP sensor voltage stays low after checking connectors, wiring, and vacuum leaks, or if you find a damaged PCM supply line, a professional will need to perform PCM diagnostics or replace the PCM itself.
Diagnostic Flowchart
Follow this visual guide to systematically diagnose P0107:
Your check engine light just came on, and the scanner shows P0107 – MAP/Barometric Pressure Circuit Low Input.
You’re not alone—thousands of drivers see this code each year, especially on Toyota, Honda, Ford, and Chevrolet models. The MAP sensor tells the engine control module (ECM) how much air is being forced into the engine. When the sensor’s voltage drops below the minimum the ECM expects, the computer assumes the intake pressure is too low, which can cause rough idle, hesitation on acceleration, and poorer fuel economy.
Below is a full‑scale, step‑by‑step guide that walks you through everything from the quickest visual checks to a complete sensor replacement. By the end of this guide you’ll know whether you can keep driving, how much the repair will cost, and when it’s time to call a professional.
Symptoms You’ll Notice While Driving
| Symptom | Why It Happens |
|---|---|
| Engine stalls at idle | The ECM receives an unrealistically low pressure reading, telling it to close the throttle too much. |
| Hesitation or stumble on acceleration | The PCM leans out the fuel mixture because it thinks the engine is under‑boosted. |
| Rough idle (fluctuating RPM) | Incorrect MAP data causes the idle air‑control valve to work harder, leading to a wobbling idle. |
| Poor fuel economy | A lean condition forces the engine to run richer later, wasting fuel. |
| Check‑engine light illuminated | The ECM logs P0107 and may also set related codes like P0102 or P0103. |
If you notice any of these signs, especially a combination of rough idle and hesitation, the MAP sensor should be high on your diagnostic list.
Root Causes (What Triggers This Code)
- Loose or damaged gas cap – A loose cap creates a vacuum leak that tricks the MAP sensor into reading low pressure.
- Corroded or unplugged MAP sensor connector – Moisture or vibration can break the electrical contact.
- Frayed wiring or broken pins – The sensor’s low‑voltage signal (typically 0.5‑4.5 V) is easily disrupted by a broken wire.
- Vacuum leaks in the hose feeding the MAP sensor – Leaks lower the pressure seen by the sensor, dropping its voltage.
- Dirty or damaged MAP sensor diaphragm – Carbon buildup or a cracked membrane reduces the sensor’s ability to sense pressure changes.
- Faulty MAP sensor itself – Internal electronics can fail, especially on high‑mileage vehicles.
- PCM supply voltage problem – A bad 5 V reference from the PCM will make every sensor read low.
These causes are not mutually exclusive; a bad connector can mask a leaking hose, so it’s best to work from the simplest checks to the more involved ones.
Step‑by‑Step Diagnosis & Repair
Safety First: Always disconnect the battery’s negative terminal before removing sensors or working on wiring. Use jack stands if you need to lift the vehicle, and keep the engine and exhaust components away from hot surfaces.
Below is the exact order you should follow. Each step includes what a good reading looks like versus a bad one, the tools you need, and the estimated time.
| # | Step | Tools | Approx. Time |
|---|---|---|---|
| 1 | Visual Inspection – Loose Cap, Connector, and Wiring | Flashlight, 10 mm socket, wire brush | 5‑10 min |
| 2 | Live Data Scan – Check MAP Voltage | OBD‑II scanner with live data | 5‑10 min |
| 3 | Multimeter Test – Sensor Ground & Reference Voltage | Digital multimeter | 10‑15 min |
| 4 | Vacuum Leak Check – Hose and Intake Inspection | Carburetor cleaner, hose/tubing, gloves | 10‑15 min |
| 5 | Sensor Cleaning – Remove Dirt or Carbon Build‑up | 10 mm socket, electronic‑grade cleaner, lint‑free cloth | 5‑10 min |
| 6 | Replace the MAP Sensor | Socket set, torque wrench, battery terminal wrench | 15‑20 min |
| 7 | Clear Codes and Verify Repair | OBD‑II scanner | 5‑10 min |
1. Visual Inspection – Loose Cap, Connector, and Wiring
Good: Gas cap clicks into place, connector snaps securely, wiring looks intact. Bad: Cap wobbles, connector pins are bent or corroded, wires show cracks or chafing.
Follow the “Visual Inspection” step listed in the front‑matter for detailed actions.
2. Live Data Scan – Check MAP Voltage
Good: MAP voltage ≈ 2.5 V at idle (sea‑level) and rises smoothly to 4.5 V when you rev the engine. Bad: Voltage stays under 0.5 V or spikes erratically.
If the voltage is low but jumps when you wiggle the connector, the problem is likely a loose plug.
3. Multimeter Test – Sensor Ground & Reference Voltage
Good: Reference wire reads ~5 V; continuity test between sensor ground and chassis shows < 0.1 Ω. Bad: No 5 V reference or high resistance (> 1 Ω) on the ground path.
A missing 5 V reference points to a PCM supply issue, which usually requires professional attention.
4. Vacuum Leak Check – Hose and Intake Inspection
Good: No hissing sound, no idle change when spraying cleaner. Bad: Audible hiss, idle speed jumps up or down when cleaner is applied.
Replace any cracked hoses; a simple hose swap often resolves a low‑input reading.
5. Sensor Cleaning – Remove Dirt or Carbon Build‑up
Good: Diaphragm looks clean, no visible oil or carbon. Bad: Dark deposits or torn membrane.
Cleaning can restore proper pressure transmission without a full sensor swap.
6. Replace the MAP Sensor
Good: New sensor installed, torque to spec, voltage returns to normal range. Bad: Sensor still reads low after installation—double‑check wiring and PCM supply.
When ordering a replacement, use the vehicle’s year, make, model, and engine size (e.g., “2017 Ford F‑150 3.5 L MAP sensor”). Prices typically range from $45‑$120 for the part alone.
7. Clear Codes and Verify Repair
After clearing, drive the vehicle for at least 10 minutes under varied conditions. If the check‑engine light stays off and performance feels smooth, the repair is successful.
Cost Breakdown (DIY vs. Shop)
| Item | DIY Parts Cost | DIY Labor (your time) | Shop Labor (average) | Dealership Quote |
|---|---|---|---|---|
| MAP sensor (OEM) | $80‑$120 | 0.5‑1 hr (incl. battery disconnect) | $80‑$120 | $150‑$200 |
| Vacuum hose (if needed) | $10‑$25 | 0.2 hr | $30‑$50 | $60‑$80 |
| Wiring repair (crimp connectors) | $5‑$15 | 0.3 hr | $40‑$70 | $80‑$120 |
| Misc. (cleaner, gloves) | $5 | – | – | – |
| Total | $100‑$160 | ≈ 1‑2 hrs | $150‑$250 | $250‑$400 |
If you already have a decent set of tools, the DIY route can save you $150‑$250. However, if you discover a broken PCM reference line or a PCM‑level fault, a shop will charge for diagnostic time and possibly a PCM replacement, which can exceed $800.
Which Vehicles Are Most Affected?
| Make | Model(s) Frequently Reporting P0107 |
|---|---|
| Toyota | Camry (2007‑2012), Corolla (2005‑2013), Tacoma (2005‑2010) |
| Honda | Civic (2006‑2011), Accord (2008‑2012), CR‑V (2007‑2012) |
| Ford | F‑150 (2009‑2014), Explorer (2011‑2015), Escape (2013‑2016) |
| Chevrolet | Silverado 1500 (2014‑2018), Cruze (2011‑2016), Equinox (2012‑2017) |
These models share a common MAP sensor design that can be prone to diaphragm wear or connector corrosion, especially in climates with high humidity
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Published: · Updated: · By Rachel Kim · Reviewed by Tom Kowalski
This guide is for informational purposes only. Always consult your vehicle's service manual and consider hiring a certified automotive mechanic for complex repairs. FixCarCodes guides are AI-assisted and reviewed for accuracy, but vehicles vary — verify part numbers and procedures for your specific make and model. Learn about our editorial process.