P0470: Exhaust Pressure Sensor A Circuit

What it means

The powertrain control module detected an electrical fault in exhaust pressure sensor A's circuit. The sensor's role and the system affected vary by vehicle.

At a glance

• Usually lights the check-engine light
• Affects emissions; the car can fail an emissions test

How it works

Exhaust pressure sensor A measures pressure through a sensor port or passage, and the control module uses its circuit signal for exhaust-system control. This code sets when the module detects an electrical fault in sensor A's circuit; the system that uses the reading varies by vehicle.

Common causes

Most likely first.

1. Exhaust pressure sensor A failure
2. Open or short in sensor wiring
3. Corroded or loose connector
4. Blocked or damaged pressure passage

Symptoms

• Check-engine light on
• Possible reduced engine power
• Possible increased exhaust smoke
• Possible reduced fuel economy

How to diagnose it

1. Record freeze-frame data and read sensor A's live pressure value and related exhaust-system data to see whether the fault is constant or operating-condition dependent.
2. Inspect sensor A's connector and wiring for looseness, corrosion, heat damage, or an open or shorted section.
3. Check the pressure passage or tube to sensor A for blockage, cracks, leaks, or damage that could interfere with the pressure reaching the sensor.
4. Compare sensor A's reading with the engine-off or operating conditions specified in vehicle service information.
5. Test sensor A's supply, ground, and signal circuit against the wiring diagram and manufacturer's specification.
6. If the circuit is sound, test sensor A itself and replace it only if its output fails the manufacturer's checks.

Common fixes

• Reconnect and secure sensor A's electrical connector.
• Clean or repair corroded or damaged connector terminals.
• Clear a blocked pressure passage or replace a cracked or damaged pressure tube.
• Repair open or shorted wiring in the sensor A circuit.
• Replace exhaust pressure sensor A if it fails testing with a sound circuit and passage.

Can I keep driving?

If the engine runs normally, a short, gentle drive may be possible, but watch for power loss or unusual exhaust smoke. Avoid towing or hard acceleration if power is reduced, and address the fault promptly because the affected exhaust controls and emissions performance can suffer.