DTC P0010400 – Intake Air Temperature (IAT) Sensor Circuit Intermittent
DTC P0010400 – Intake Air Temperature (IAT) Sensor Circuit Intermittent
✅ DTC P0010400 – Intake Air Temperature (IAT) Sensor Circuit Intermittent
📌 Meaning
This code indicates that the IAT sensor signal is cutting in and out (not stable).
The ECU receives a temperature reading sometimes, then loses it → electrical connection is unstable.
🔧 Common Causes
1. Loose or corroded IAT sensor connector
2. Damaged wiring / broken wire inside insulation
3. Intermittent short to ground or short to power
4. Poor contact in ECU pin
5. Faulty IAT sensor (internal open circuit)
6. Aftermarket air filter / intake pipe not installed properly (sensor left hanging loose)
🧰 Step-by-Step Diagnostic Procedure
✅ 1. Visual Inspection (Most important for intermittent faults)
Inspect the IAT sensor plug
Check for:
Loose connector
Bent pins
Green corrosion
Broken locking tab
Gently move the wiring while engine is idling → if the code appears, wiring is faulty.
✅ 2. Wiring Test
Perform a wiggle test on the harness.
Check continuity of:
IAT signal wire → ECU
IAT ground wire → ECU
If continuity breaks when you shake the wire:
🔧 Replace/repair wiring.
✅ 3. Check IAT Sensor Resistance
Most IAT sensors are NTC type (resistance decreases as temperature increases).
Typical values (varies by vehicle):
0°C → 10–12 kΩ
20°C → 2–3 kΩ
40°C → 1 kΩ
If resistance jumps or drops randomly → sensor is bad.
✅ 4. Check for 5V Reference and Ground
Key ON
Check the IAT connector:
One wire should have 5V
One should be ground If voltage is intermittent → wiring or ECU pin problem.
✅ 5. Scan Data Monitoring
Monitor IAT sensor live data
Check for:
Sudden jumps (e.g., 35°C → -20°C → 80°C)
Fluctuating values when touching the harness
If data fluctuates → intermittent fault confirmed.
✅ 6. Replace IAT Sensor if Needed
If all wiring is good, replace the sensor (common & inexpensive fix).
🚗 Most Common Repair in Workshops
🦋 Cleaning and tightening the IAT connector
🦋 Replacing a cracked IAT wiring section near air filter box
🦋 Replacing the IAT sensor
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