OBD Code P1124: Manifold Absolute Temperature Circuit High Input

Q: What does OBD code P1124 mean?

Manifold Absolute Temperature Circuit High Input. Your engine's computer detected that the intake manifold air pressure sensor is reading too high, like a barometer stuck on a reading that doesn't match actual conditions. This tricks the engine into thinking there's more air than there actually is, causing it to run rich.

Q: What are the symptoms of fault code P1124?

Check Engine Light illuminated, Rough idle or stalling, Poor fuel economy and black smoke from exhaust

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What This Actually Means

In plain language — no jargon

Your engine's computer detected that the intake manifold air pressure sensor is reading too high, like a barometer stuck on a reading that doesn't match actual conditions. This tricks the engine into thinking there's more air than there actually is, causing it to run rich.

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Symptoms You May Notice

3 known symptoms for this code

Check Engine Light illuminated

Rough idle or stalling

Poor fuel economy and black smoke from exhaust

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How Your ECU Detects This

Technical sensor logic and voltage thresholds

The ECU monitors voltage from the MAP (Manifold Absolute Pressure) sensor, which indicates intake manifold pressure. When voltage exceeds the maximum threshold, the ECU logs a fault because it indicates either a sensor malfunction or an impossible pressure reading.

Voltage & Parameter Thresholds

Parameter	Normal Range	Fault Condition
MAP Sensor Voltage	0.5V - 4.5V	>4.8V detected
Manifold Pressure Reading	10-105 kPa	Reading exceeds system maximum

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Diagnostic & DIY Fix Guide

Check these in order — from cheapest to most complex

1

MAP sensor connector

Inspect and reseat the connector at the sensor to eliminate corrosion or loose contact.

2

MAP sensor wiring harness

Check wiring for damage, pinches, or exposed conductors and repair any visible defects.

3

MAP sensor

Replace the sensor if connector and wiring are clean; the sensor itself has likely failed internally.

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When to See a Professional Mechanic

Not all fault codes are safe to DIY

Code P1124 is a moderate fault. You can generally drive to a workshop, but avoid long trips or high-load driving (motorway, uphill towing) until it is diagnosed. If the code keeps returning after clearing, or if you notice the symptoms listed above worsening, do not delay professional diagnosis. Many moderate codes have multiple possible root causes — a mechanic with live OBD data can identify the exact fault more efficiently than part-by-part trial and error.

Safety note: OBD-II codes identify the system or circuit where a fault was detected — they do not always identify the exact failed component. A professional mechanic using live sensor data will diagnose the root cause more accurately than replacing parts based on the code alone.

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How to Clear Code P1124

What happens after you fix the fault

Once the fault is repaired, P1124 can be cleared using any OBD-II scanner. Connect the scanner, navigate to "Clear Codes" or "Erase DTCs," and confirm. The check engine light turns off immediately.

The code will return if the root cause was not actually fixed. The ECM re-detects the fault within 1–3 drive cycles and sets the code again.

✅ Safe to Clear When

Fault has been diagnosed and repaired
You want to confirm the repair worked
Code appeared after a sensor was cleaned

⚠️ Do Not Clear When

Preparing for an emissions/PUC test
Root cause is still undiagnosed
Check engine light is flashing

Emissions test note: Clearing codes resets OBD readiness monitors. Most vehicles need 50–100 km of mixed driving before monitors complete. Do not clear codes immediately before an emissions or PUC inspection.