Code
P2E80
Generic
P — Powertrain
A/C Compressor Control Module InternalTemperature Sensor B Circuit Intermittent/Erratic
Views:
UK: 13
EN: 26
RU: 18
AI status
Completed
Completed
100%
Causes
- Loose, corroded, or damaged connector at the A/C compressor control module
- Frayed, chafed, or shorted wiring in the sensor signal, reference, or ground circuit
- Water intrusion or corrosion in the harness or connector
- Intermittent internal failure of the temperature sensor (thermistor) inside the compressor module
- Faulty A/C compressor control module electronics
- Low or unstable battery/charging system voltage or poor ground
Symptoms
- Intermittent A/C cooling or sporadic compressor engagement
- HVAC temperature fluctuates or does not match set temperature
- MIL/check-engine lamp or A/C-related warning illuminate
- Stored or pending DTC P2E80 (or similar) in scan tool
- Compressor cycles on/off unexpectedly or runs continuously in some conditions
What to check
- Read and record all stored/pending codes and freeze-frame data with a scan tool; note when the code sets
- Visually inspect wiring and connectors at the compressor for corrosion, damage, pin push-out, or water intrusion
- Wiggle test wiring harness and connectors while monitoring live sensor data to try to reproduce the intermittent behavior
- Backprobe sensor signal, reference (usually 5V or ignition-switched reference), and ground with key ON and monitor voltages
- Measure continuity and resistance between the compressor module connector and the PCM/ECU where applicable
- Check vehicle battery/charging system voltage and engine chassis ground integrity
Signal parameters
- Sensor type: typically an NTC thermistor (resistance changes with temperature)
- Reference voltage: commonly a stable 5 V reference from the module or PCM (verify for vehicle)
- Expected signal voltage: normally varies with temperature within a 0.5–4.5 V range (vehicle-specific)
- Open-circuit condition: signal voltage near battery voltage or near 0 V (depending on circuit design) or very high resistance (> tens to hundreds of kΩ)
- Short-to-ground/short-to-VB conditions will drive the signal to near 0 V or near battery voltage respectively
- Intermittent fault: signal will rapidly jump or drop, show noisy/unstable waveform, or drop in/out intermittently
Diagnostic algorithm
- Connect a capable scan tool and confirm P2E80 is present; record freeze-frame and live data for the internal temperature B signal while cycling HVAC and compressor states.
- Visually inspect the compressor control module connector and harness for damage, corrosion, moisture, or rodent chew. Repair or replace any damaged sections.
- With connector seated, backprobe the signal, reference, and ground pins. With ignition ON (engine off if required), verify reference voltage (≈5V), stable ground, and that the signal voltage responds to ambient temperature or changes smoothly.
- Perform a wiggle test on the harness and connector while monitoring live data to try to reproduce the intermittent/erratic signal. Inspect any areas where wires pass through body panels or near moving parts.
- If intermittent persists, disconnect the compressor module and measure the internal sensor resistance at the module connector across the sensor terminals (compare to vehicle-specific temperature/resistance chart if available).
- Check continuity from the connector to the PCM or HVAC control module on signal and ground circuits; repair any opens or high-resistance connections.
- Verify stable supply voltage to the compressor control module under load; inspect and clean ground points. Repair as needed.
- If wiring and connectors check good but the intermittent fault remains and sensor resistance/response is out of spec or inconsistent, consider replacement of the A/C compressor control module (or internal sensor assembly) per service manual.
- After repairs, clear codes, perform the required A/C system relearn or initialization (if applicable), then road-test and monitor live data to confirm the fault does not return.
- Safety note: avoid damaging refrigerant lines when accessing the compressor. Follow vehicle-specific service procedures for removing/replacing the compressor module.
Likely causes
- Corroded or loose connector at the compressor control module
- Damaged wiring harness near condenser, compressor, or routing points
- Intermittent internal sensor element failure in the compressor module
- Poor ground or intermittent supply voltage to the compressor control module
- Failed compressor control module
Fault status
Status
Intermittent/erratic signal detected from A/C compressor control module internal temperature sensor B circuit. Signal fluctuates or is dropping in/out beyond allowed thresholds.
Repair difficulty: Medium
Diagnostic time: 1.5-3.0 hours
Similar codes
Workshop Manuals
Available brands with manuals
2
AUDI 11
6-speed manual gearbox 0B1, front-wheel drive — Workshop Manual (Edition 05.2014)
Workshop Manual199,00 UAH
Audi A3 (1997) – 1.6L 4-cylinder (2‑valve) Engine Mechanical Components Service Manual (AEH, AKL, APF) – Edition 07.2002
Workshop Manual199,00 UAH
AUDI A3 (2004) Workshop Manual — 2.0L FSI Turbo (4‑cyl, 4‑valve) Engine, Mechanics — Edition 03.2017
Workshop Manual199,00 UAH
Audi A3 2004 — Electrical System (Workshop Manual, Edition 02.2018)
Workshop Manual199,00 UAH
Audi A4 / A4 Cabriolet – 4.2 l V8 (5‑valve, timing chains) – Workshop Manual (Mechanics) – Edition 04.2007
Workshop Manual199,00 UAH
Audi A4 / A4 Cabriolet — Auxiliary Heater Workshop Manual (Edition 08.2004)
Workshop Manual199,00 UAH
Audi A4 / A4 Cabriolet (1.8T 4‑cyl turbo) — Motronic Injection & Ignition System Service Manual (Edition 01.2015)
Workshop Manual199,00 UAH
Audi A8 (2003) — Electrical System Workshop Manual (Edition 08.2014)
Workshop Manual199,00 UAH
Audi Q4 e-tron (Type F4) - Self-study Programme SSP 685
Workshop Manual199,00 UAH
Audi Q8 (2018) — Electrical System Workshop Manual (Edition 05.2019)
Workshop Manual199,00 UAH
Audi Servicing Manual — 7‑Speed Dual Clutch Transmission 0CJ / 0CL / 0CK / 0DN / 0DP / 0HL (Edition 05.2018)
Workshop Manual199,00 UAH
LAND ROVER 3
Land Rover Defender 300Tdi — Workshop Manual (1996 model year)
Workshop Manual199,00 UAH
Land Rover Defender Workshop Manual Supplement & Body Repair Manual (1999 & 2002 MY)
Workshop Manual199,00 UAH
Land Rover Range Rover — Electrical Library (LRL 0453ENG, 2002)
Workshop Manual199,00 UAH
Your experience will help others
+100 karma for a short comment :)
Was this AI description helpful?
Your feedback helps improve AI descriptions.
👍 Like
0
👎 Dislike
0
Send to email
