P011C

Charge Air Temperature/Intake Air Temperature Correlation Bank 1

P011C is a generic OBD-II powertrain diagnostic trouble code: Charge Air Temperature/Intake Air Temperature Correlation Bank 1. It is logged by the engine control unit when the powertrain monitor detects that a specific fault threshold has been exceeded — typically resulting in the malfunction-indicator lamp (MIL / check-engine light) being illuminated.

Code
P011C
Group
Powertrain
System
Powertrain
Severity
Warning (MIL on)
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What P011C means

Code P011C is stored when the powertrain control module (PCM) detects a significant discrepancy between the signal from the charge air temperature (CAT) sensor and the intake air temperature (IAT) sensor on engine bank 1 — the bank containing cylinder number one. Both sensors measure air temperature at different points in the forced-induction path: the CAT sensor reads air temperature exiting the intercooler (charge air cooler), while the IAT sensor reads temperature entering the intake manifold. Under normal conditions the two readings track closely once the intercooler has stabilised; when the PCM calculates a voltage or temperature difference that exceeds its programmed threshold, it flags P011C. This code is exclusive to turbocharged and supercharged engines with multiple air inlet sources. A faulty sensor, wiring fault, or blocked intercooler can all shift one reading relative to the other. Prolonged operation with this fault can skew fuel trim and spark-advance calculations, reducing power and efficiency, though driveability is rarely catastrophic.

Common causes

Most-frequently reported root causes when P011C is logged.

  • 1
    Faulty charge air temperature (CAT) sensor on bank 1 — out-of-range resistance or drift
  • 2
    Faulty intake air temperature (IAT) sensor — incorrect voltage signal sent to PCM
  • 3
    Damaged, corroded, or shorted wiring and connectors in the CAT or IAT sensor circuits
  • 4
    Intercooler (charge air cooler) blockage or efficiency loss causing abnormal temperature differential
  • 5
    Air leak in the charge air ducting between the turbo outlet and the throttle body
  • 6
    Defective or contaminated thermistor element inside either sensor
  • 7
    Failed or miscalibrated PCM (rare)

Symptoms drivers notice

Malfunction indicator lamp (MIL / check engine light) illuminated
Reduced engine power or sluggish throttle response, especially under boost
Increased fuel consumption due to incorrect air-charge calculations
Rough idle or hesitation during acceleration
Possible boost-related performance concerns on turbocharged vehicles

How to diagnose P011C

A typical diagnostic flow when this code is present.

  1. 1
    Connect an OBD-II scanner, record P011C and any co-stored codes, and capture freeze-frame data to note engine load and temperature at time of fault
  2. 2
    Visually inspect the intercooler, charge air piping, and all intake ducting for cracks, loose clamps, or blockages that could distort air temperature
  3. 3
    Inspect wiring harnesses and connectors for both the CAT and IAT sensors — look for chafing, corrosion, pushed-back pins, or moisture intrusion
  4. 4
    Unplug each sensor and measure resistance with a DVOM at known ambient temperature; compare readings against manufacturer specifications (typical NTC thermistor range)
  5. 5
    With the ignition on (engine off), monitor live scanner data for both sensor temperatures and confirm they read within a few degrees of each other and of ambient
  6. 6
    Apply heat carefully to each sensor while monitoring scanner data to verify sensor response is smooth and within spec
  7. 7
    Replace the out-of-spec sensor, repair any wiring faults, then clear the code and complete a full drive cycle to confirm the repair

Related powertrain codes

Frequently asked questions

Can P011C be triggered by altitude or cold weather alone?

Unlikely. Ambient conditions affect both sensors equally, so a genuine correlation fault points to a hardware issue rather than environmental variation.

Is it safe to keep driving with P011C active?

Short term yes, but fuel trim and ignition timing may be compromised, reducing efficiency and potentially stressing the engine under load. Diagnose promptly.

Which sensor should I replace first — CAT or IAT?

Test both with a DVOM before replacing either. The sensor whose resistance deviates most from the manufacturer curve is the likely culprit.

Could a dirty air filter cause P011C?

A severely clogged filter can restrict airflow and heat soak the charge air path, but P011C is more commonly caused by a sensor or wiring fault rather than a filter issue.

Disabling P011C in software

RaceTune can permanently disable P011C — and any other OBD-II diagnostic trouble code — on every ECU family we support. The monitor is disabled inside the ECU itself, so the fault stops being logged: the warning light stays off and the engine never enters limp mode for this code. The change is tied to your exact software version.

Permanent
The monitor is disabled in the ECU itself — not just cleared. It cannot return.
Tailored to your file
Each patch is matched to your specific software version — never a one-size-fits-all file.
Reversible
The original file is always preserved. Reflash the stock to return the ECU to factory state.

Software modifications affect emissions compliance and are not road-legal in many jurisdictions. RaceTune service files are intended for motorsport, off-road, and export use.

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