Code
P0108
MITSUBISHI
P — Powertrain
BARO./MAP sensor high
Views:
UK: 11
EN: 20
RU: 30
AI status
Completed
Completed
100%
Causes
- Faulty MAP or BARO sensor
- Short to battery/5V in the sensor signal circuit
- Open or poor sensor ground
- Wiring damage (chafed, corroded, pinched) or connector corrosion/contamination
- Blocked or restricted MAP sensor port/vacuum hose
- PCM input fault or internal failure
Symptoms
- Check Engine Light (MIL) ON with P0108 stored
- Engine may run rich, poor idle, or have reduced drivability
- Possible hesitation, surging, or loss of power
- Unusual boost behavior on turbocharged engines
- Poor fuel economy
What to check
- Read freeze frame and pending codes with a scan tool; note conditions (rpm, load, temp) when code stored
- Observe live MAP/BARO sensor PID(s) with scan tool at key-on and engine-off, idle, and under load
- Visually inspect sensor connector, wiring harness and vacuum/boost lines for damage, contamination or disconnected hoses
- Backprobe sensor signal, reference and ground with a multimeter or lab scope
- Compare MAP sensor signal to BARO (key ON engine OFF BARO should equal MAP reading)
- Check for applicable technical service bulletins (TSBs) or software updates
Signal parameters
- MAP/BARO sensors are typically ratiometric to the reference voltage; expected signal range roughly 0.5–4.5 V (higher voltage = higher pressure). Verify exact spec in Mitsubishi service manual.
- At key ON, engine OFF: BARO should read ambient pressure (sensor voltage should match BARO PID).
- At idle: MAP should be lower than BARO when intake is under vacuum; under boost/load MAP voltage will increase. Use scan tool kPa or inHg values to compare to atmospheric conditions.
Diagnostic algorithm
- Connect a professional scan tool and confirm P0108 and related codes; record freeze frame data.
- With key ON engine OFF, record BARO and MAP sensor voltage/pressure from the scan tool. They should be equal — if MAP is higher than BARO, suspect MAP circuit or sensor.
- Visually inspect the MAP sensor, vacuum/boost hoses and port. Clear any debris; replace broken or collapsed hoses.
- Backprobe the MAP sensor connector: verify reference voltage (usually ~5V) with key ON, good continuity to ECU, and a good ground. Repair any wiring faults before replacing the sensor.
- Using a multimeter or lab scope, check the MAP signal while varying intake pressure (apply vacuum or run engine). Look for intermittent spikes, stuck-high reading, or signal pinned to 5V/12V.
- If wiring and reference/ground are good but signal remains incorrect, swap with a known-good sensor (or install new OEM sensor) and verify the code clears and readings normalize.
- If replacement sensor does not fix the issue, check PCM input circuit for shorts/open or perform ECU diagnostics per factory procedure. Consider professional ECU testing/repair.
- Clear codes and perform a road test under the same conditions that set the code to confirm repair. Re-scan to ensure code does not return.
Likely causes
- Failed MAP/BARO sensor (most common)
- Damaged signal wire shorted to 12V at harness or connector
- Loose/corroded connector or poor ground at sensor
- Blocked MAP port or stuck sensor diaphragm (intake contamination)
Fault status
Status
PCM detected MAP/BARO sensor circuit high voltage (sensor reporting excessive pressure or electrical fault).
Repair difficulty: Medium
Diagnostic time: 1.0-2.5 hours
Similar codes
Your experience will help others
+100 karma for a short comment :)
Was this AI description helpful?
Your feedback helps improve AI descriptions.
👍 Like
0
👎 Dislike
0
Send to email