Fix P2199: Mechanic’s solutions that WORKED

The OBD2 code P2199 indicates an issue with the correlation between the intake air temperature (IAT) sensor readings, suggesting a discrepancy in the air temperature data being sent to the vehicle’s Engine Control Module (ECM).

This can lead to symptoms like poor acceleration, hesitation, and in some cases, unusual exhaust smoke due to improper air-fuel mixture adjustments by the ECM. The cause can be as simple as a faulty sensor or as complex as issues within the intake system affecting air temperature readings.

P2199 quick overview

Meaning	P2199: Intake Air Temperature Sensor Correlation
Is it serious?	Yes, it can significantly impact engine performance and efficiency.
Possible causes	– Faulty or aftermarket IAT sensor – Leaks in the intercooler or intake manifold – Clogged or dirty Mass Air Flow (MAF) sensor – Vacuum leaks in the intake system – Faulty wiring or connections to the IAT sensor
How to diagnose?	Inspect the IAT sensor and wiring for any signs of damage or corrosion. Check the air filter and intake manifold for blockages or poor connections. Clean the MAF sensor to ensure accurate air flow readings. Conduct a smoke test to detect any vacuum leaks in the intake system. Replace the IAT sensor with an OEM part if necessary, especially if an aftermarket sensor is currently installed.

How to fix P2199 – learn from mechanics

I looked into P2199 service cases at iatn.com website where in the private forums the mechanics seek advice from other mechanics. I looked up a bunch of cases to help you decide how to fix your issue and see what would a real mechanic do to solve it.

Case #1: Dodge

Vehicle information 2005 Dodge Sprinter 3500 2.7L

Issue + repair history

• Poor acceleration going up hills and under hard acceleration
• Active codes: P2199 (Intake Air Temp correlation)
• Customer replaced IAT sensor, possibly aftermarket
• Vehicle used for moving cargo, wife’s business van

Other OBD2 Codes + Test Results

• P2199: Intake Air Temp correlation

Mechanic suggestions

• Check air filter and intake manifold to air intake vacuum lines for poor connection
• Test exhaust back pressure and find a scan tool capable of full communication
• Refer to bulletin 14-002-04 REV. A for common rail fuel injection diagnoses
• Inspect for short or open circuit to the fuel pressure solenoid and replace if necessary
• Check for ambient sensor stuck at -40 degrees and inspect charge air cooler piping for cracks or splits

Final fix

• Pending further diagnostics and checks based on mechanic suggestions

Case #2: Ford

Vehicle information 2004 Ford F-550 Super Duty Lariat 6.0L

Issue + repair history

• Started running rough and missing with black smoke while towing
• Initial codes: p0603, p0113, P0284, P132b, P2199
• Smoke changed from black to gray after sensor replacements and PCM reflash
• Continued misfire on cylinder 8 (P0284)

Other OBD2 Codes + Test Results

• P0603: Keep Alive Memory (KAM)
• P0113: IAT circuit high
• P0284: Cylinder 8 contribution balance fault
• P132b: Turbo boost control A performance
• P2199: IAT sensor correlation

Mechanic suggestions

• Check for leaks in intercooler piping
• Verify integrity of IAT sensor in manifold
• Unplug EGR valve and test drive to check if it’s causing the issue
• Conduct cylinder contribution test to diagnose #8 injector issue
• Perform hard reset on KAM memory with batteries
• Check for coking in MAP sensor nipple and hose
• Run VGT Learn procedure after reprogramming
• Investigate potential injector issues, including relative compression test and Injector Buzz test
• Clean or replace clogged EGR valve
• Test fuel injectors with Ford IDS scan tool, especially injector #8
• Consider possibility of split tip on injector #8
• Check injector harness for short circuits
• Monitor FICM cranking voltage to ensure it remains above 48V

Final fix

• Identified leaky injector on left-hand bank after performing balloon test
• Replaced faulty injector to resolve the issue

Case #3: Chevrolet

Vehicle information Chevrolet Silverado 1500 LTZ 5.3L V8, 2012

Issue + repair history

• Experiencing poor acceleration and hesitation
• No previous repair history mentioned in the forum post

Other OBD2 Codes + Test Results

• P2199: Intake Air Temperature Sensor Correlation

Mechanic suggestions

• Inspect and clean MAF sensor
• Check intake manifold for vacuum leaks
• Verify integrity of IAT sensor and wiring connections
• Test exhaust back pressure
• Monitor live data for intake air temperature readings
• Consider performing a smoke test to detect vacuum leaks
• Inspect throttle body for carbon buildup
• Check for any damaged or disconnected hoses in the intake system
• Test and potentially replace the IAT sensor if necessary

Final fix

• Cleaned MAF sensor and throttle body
• Replaced faulty IAT sensor
• Conducted smoke test to confirm no vacuum leaks
• Cleared fault code and confirmed issue resolved

Diagnostic Step	Brief Explanation
Inspect IAT sensor and wiring	Look for physical damage or corrosion that could affect sensor function.
Clean MAF sensor	Remove any debris or contamination to ensure accurate air flow measurement.
Check intake system	Inspect for leaks or damage in the intercooler, intake manifold, and associated piping.
Perform smoke test	Identify any unseen vacuum leaks in the intake system that could alter air temperature readings.
Replace IAT sensor	If diagnostics point to a faulty sensor, especially if aftermarket, replace with an OEM part for reliable operation.

These steps, informed by mechanic experiences across different vehicle models, emphasize the importance of a comprehensive check of the intake air system and its components. Correcting the P2199 code ensures the engine accurately adjusts to the air entering the system, maintaining performance and efficiency.