Is your Mini Countryman, Mini Cooper Hatch, or BMW 1 Series displaying a "Drivetrain Malfunction" warning? If your scan tool reveals code P0108 (or BMW hex code 10804), you are dealing with an Intake Manifold Pressure Sensor issue.
In this technical guide, analyzed from a real-world repair by SA Diagnostic's, we will explore why this happens on the popular 1.5L Petrol (B38) engine and how to fix it correctly using the iCarsoft CR ULTRA P.
The MAP sensor monitors the air pressure entering the engine to calculate fuel injection.
Understanding Fault Code P0108
Definition: P0108 stands for Manifold Absolute Pressure (MAP) Circuit High Input.
This means the sensor is sending a voltage signal to the Engine Control Unit (ECU) that is higher than the expected range (often indicating full atmospheric pressure when there should be a vacuum). This confuses the ECU, leading to:
- Limp Mode (reduced power).
- Poor fuel economy.
- Rough idling.
Authoritative Resource: How Manifold Pressure Sensors Work (Bosch Mobility).
Video Tutorial: Sensor Location & Cleaning
Watch the technician locate and inspect the sensor on a Mini Countryman:
Step-by-Step Fix Strategy
1. Check the Wiring First
Before buying parts, the video advises: "Check the wiring, make sure there's power."
Use your multimeter or the Live Data function on your iCarsoft CR ULTRA P. If the sensor reads a static value (e.g., 5V or max pressure) that doesn't change when you rev the engine, but the wiring looks good, the sensor is likely the culprit.
2. The "Clean Attempt"
Sometimes, oil vapor or carbon can clog the sensor port.
- Unclip the wiring harness.
- Remove the sensor (usually held by one screw).
- Spray the sensor element gently with Electrical Contact Cleaner or MAF Sensor Cleaner.
- Let it dry completely and reinstall.
Verification: This step is useless if you don't clear the code. Use the CR ULTRA P to "Full Scan and Clear" the fault. Start the engine. If the code stays gone, you saved money!
Always match the part number exactly. Aftermarket sensors often fail on BMW systems.3. Replace with OEM Only
If cleaning fails, you must replace the sensor. The technician is very clear:
"Get original OEM sensor... otherwise you're going to be in the same boat guys every time."
Aftermarket sensors for BMW/Mini often have slight resistance variations that trigger the P0108 code immediately. Look for brands like Bosch or Continental (who often make the genuine part).
Why Accurate Diagnostics Matter
On modern BMW platforms (F-Series, G-Series), a generic code reader might just say "P0108". However, the iCarsoft CR ULTRA P dives deeper, often providing BMW-specific hex codes (like 108001 or 108004) that pinpoint if the issue is a short to positive or an open circuit.
Related Guide: Why you need a BMW-specific scan tool for maintenance.
Frequently Asked Questions (FAQ)
Is P0108 serious?
Yes. While it usually won't destroy the engine immediately, it forces the car into a safety map ("Limp Mode"), reducing turbo boost and power. Long-term driving can damage the catalytic converter due to incorrect fueling.
What other cars use this engine?
This guide applies to the BMW B38 1.5L engine, found in:
- Mini One / Cooper (F55/F56)
- Mini Countryman (F60)
- BMW 1 Series (F40)
- BMW 2 Series Active Tourer
- BMW 3 Series (318i)
Does the CR ULTRA P support BMW Battery Registration?
Yes. If you also need to replace your battery while fixing this issue, the CR ULTRA P can perform the mandatory BMS (Battery Management System) registration for BMW and Mini. See full functions here.
Fix Your "Drivetrain Malfunction" Now.
Don't guess with expensive parts. Diagnose, Clear, and Verify with the iCarsoft CR ULTRA P.
