P2AC8: Charge Air Cooler Coolant Temperature Sensor B Range/Performance

What it means

The charge air cooler coolant temperature B signal does not match plausibility checks against related signals. Sensor drift.

At a glance

• Usually lights the check-engine light

How it works

Charge air cooler coolant temperature sensor B reports the temperature of the coolant used to cool the intake air. The control module compares its reading with related temperatures and operating conditions; this code sets when sensor B appears plausible electrically but its reading does not track those checks.

Common causes

Most likely first.

1. Sensor fault
2. Wiring or connector fault

Symptoms

• Check-engine light may be on
• Reduced engine power
• Poor acceleration, especially under load

How to diagnose it

1. Use a scan tool to save freeze-frame data and compare sensor B with other coolant and intake-air temperature readings under the recorded conditions.
2. With the engine cold, compare sensor B's reading with ambient temperature and other temperature sensors for an implausible offset.
3. Inspect sensor B's connector and wiring for corrosion, loose pins, damaged insulation, or heat damage.
4. Check sensor B's signal and ground circuits for poor connections or resistance that could shift the reading.
5. Test sensor B against the manufacturer's specification as its temperature changes, and replace it if its response is inaccurate.

Common fixes

• Clean and secure the sensor B connector if its contacts are dirty or loose.
• Repair damaged wiring or poor signal and ground connections in the sensor B circuit.
• Replace charge air cooler coolant temperature sensor B if its reading drifts outside specification.

Can I keep driving?

If the engine runs normally, a short, gentle trip may be possible, but avoid towing, hard acceleration, and sustained high load because reduced power or poor acceleration can worsen. Arrange diagnosis soon, especially if power drops noticeably.