P00AB
Intake Air Temperature Sensor 1 Circuit Range/Performance Bank 2P00AB is a generic OBD-II powertrain diagnostic trouble code: Intake Air Temperature Sensor 1 Circuit Range/Performance Bank 2. 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.
What P00AB means
DTC P00AB is stored when the PCM detects that the Bank 2 IAT Sensor 1 (IAT1) signal voltage is changing faster than is physically possible for the actual air temperature, or is reading outside the plausible range given other engine parameters. Unlike P00AA (general circuit malfunction) or P00AC (fixed low voltage), the "Range/Performance" descriptor indicates the signal is technically within the circuit's electrical bounds but is behaviourally implausible — for example, jumping 30 °C in one second, or reading a temperature inconsistent with the coolant sensor when the engine is cold-soaked. The IAT1 sensor is a two-wire NTC thermistor supplied a 5 V reference by the PCM; the PCM calculates temperature from the ratio of signal voltage to reference. A sensor with a degraded or cracking thermistor element, a loose terminal, or a signal wire picking up electrical noise from adjacent ignition components can all cause readings to exceed the PCM's rate-of-change plausibility limit. Because fuel delivery and ignition timing rely on accurate air temperature data, a range/performance fault causes fuel trim errors that appear as rough running, hesitation, and inconsistent idle — often more noticeable under varying load or temperature conditions.
Common causes
Most-frequently reported root causes when P00AB is logged.
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1
Internally degraded IAT1 sensor with non-linear resistance response (most common) — causes signal to jump suddenly during temperature changes
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2
Open circuit on the ground wire producing a floating signal that shifts unpredictably
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3
Short to ground on the signal wire that causes voltage to suddenly collapse when a specific harness position is reached
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4
Electrical interference from ignition wires or injector wiring routed parallel to the IAT1 signal wire
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5
Loose or corroded connector terminal that connects and disconnects intermittently under vibration
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6
Cracked or damaged sensor body allowing moisture ingress that alters thermistor resistance unpredictably
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7
PCM reference voltage instability causing the IAT1 ratio calculation to appear out of range
Symptoms drivers notice
How to diagnose P00AB
A typical diagnostic flow when this code is present.
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1
Retrieve P00AB with a scan tool; check for companion codes (MAF, other IAT, O2 sensor) and review freeze-frame to note coolant temperature, IAT1 Bank 2 voltage, and engine load at fault trigger
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2
With ignition on and engine cold, verify the Bank 2 IAT1 reading matches the coolant temperature sensor within a few degrees — a mismatch on a cold engine points to a performance issue rather than a stuck circuit
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3
Unplug the IAT1 Bank 2 sensor and perform a thermal resistance test: measure resistance at room temperature, then cool the sensor in a freezer (allow 5 minutes) and heat with a heat gun — resistance should transition smoothly; any sudden jump or spike during transition confirms a failing thermistor
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4
With the sensor reinstalled and ignition on, backprobe the signal circuit with a voltmeter and perform a vigorous wiggle test along the harness from sensor to PCM; any sudden voltage change during flexing identifies the fault location
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5
Inspect the signal wiring route for proximity to high-voltage ignition cables, injector wiring, or alternator output — reroute or add shielding if electromagnetic interference is suspected
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6
Check the PCM-side ground for the IAT1 Bank 2 circuit; a degraded PCM ground can destabilise the reference voltage and produce range/performance faults across multiple sensor inputs
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7
Replace the sensor if thermal testing reveals non-linear response; repair identified wiring faults, clear the code, and confirm over multiple drive cycles with varying temperatures
Related powertrain codes
Frequently asked questions
What makes a 'Range/Performance' fault different from a 'Circuit High' or 'Circuit Low' fault?
Circuit High and Circuit Low codes indicate the voltage is outside the sensor circuit's electrical limits (above 4.9 V or below 0.1 V). Range/Performance means the voltage is within electrical limits but the reading is behaviourally implausible — it changes too quickly or contradicts what other sensors indicate about current engine conditions. Range/Performance faults are harder to catch because the circuit appears electrically intact.
Why does P00AB sometimes appear only in cold weather?
Cold weather causes connector metals to contract, worsening marginal terminal contact, and also stresses degraded thermistor elements that crack slightly under thermal contraction. A sensor that reads plausibly in warm conditions may produce sudden resistance jumps when cold, triggering the PCM's rate-of-change monitor and setting the code.
Can electromagnetic interference from ignition components really cause P00AB?
Yes. The IAT signal circuit operates at low voltage (0–5 V) and is susceptible to noise from high-voltage ignition wires routed in parallel. Induced voltages can appear as rapid signal fluctuations that the PCM interprets as an implausible rate of change. Rerouting the harness away from ignition components or adding a shielded wire can resolve the issue.
Is it worth trying to clean the connector before replacing the sensor for P00AB?
Yes — cleaning the connector with electrical contact cleaner and ensuring all terminals are fully seated is a free first step that resolves a meaningful percentage of range/performance faults. Only if cleaning and wiggle-testing confirm the connector is sound should you proceed to sensor replacement.
Disabling P00AB in software
RaceTune can permanently disable P00AB — 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.
ECU families we can disable P00AB on
We hold the DaVinci A2L disable definitions for these families, so the exact P00AB path and mask addresses are mapped. verified marks a confirmed disable definition. We support many more — upload your file and our identifier will match it automatically.
- Bosch EDC17C66 verified
- Bosch EDC17CP57 verified
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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