What it means
The ECM detects a circuit high fault on the turbocharger/supercharger a temperature sensor. Reading cannot be used reliably for control.
At a glance
- Usually lights the check-engine light
- Affects emissions; the car can fail an emissions test
How it works
Turbocharger or supercharger A’s temperature sensor reports heat to the engine control module for forced-induction management. P2B70 sets when its signal is higher than expected, which can result from a signal wire shorted to battery voltage, an open sensor, or high resistance at a connector.
Common causes
Most likely first.
- Signal wire shorted to B+
- Open sensor
- Connector pins corroded - high contact resistance
Symptoms
- Check engine light on
- Significant power loss / limp mode
- Possible blue or black smoke from exhaust
- Whistling or hissing sound from intake
How to diagnose it
- Record freeze-frame data and check the live sensor A temperature reading to see whether it is implausibly high, especially when cold.
- Inspect sensor A’s connector and harness for a signal wire contacting a power feed, an open circuit, corrosion, or heat damage.
- Check the sensor circuit’s signal, reference, and ground against the wiring diagram and manufacturer’s specification.
- Test the harness for a short to battery voltage and continuity between sensor A and the engine control module.
- If the harness is sound, test sensor A for an open circuit and compare its output with the manufacturer’s specification.
Common fixes
- Clean and secure corroded sensor A connector pins.
- Repair a signal wire short to battery voltage or an open in the harness.
- Repair a poor connector contact causing excessive resistance.
- Replace turbocharger or supercharger A’s temperature sensor if it is open.
Can I keep driving?
Avoid hard acceleration and boost until the signal fault is corrected, particularly if power is reduced, smoke appears, or the intake hisses. An incorrectly high reading can prompt protective operation, and an underlying intake or exhaust problem may worsen.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.