Exhaust Pressure Sensor "A" Circuit
The P0470 code indicates the exhaust pressure sensor is not reading correctly or has lost communication with the engine control module. This sensor monitors exhaust gas pressure to optimize turbocharger and emissions control system operation, and failure prevents proper engine performance and regeneration cycles.
What You Might Notice
- Check Engine Light illuminated
- Loss of engine power and acceleration
- Unable to perform passive or active diesel particulate filter regeneration
- Reduced fuel economy
- Engine may enter limp mode or derate power output
Most Common Causes
- 1
Blocked sensor tube or line
The pressure line running from the exhaust manifold or turbocharger to the sensor becomes clogged with soot or carbon deposits, blocking pressure signal transmission.
- 2
Defective exhaust pressure sensor
The sensor itself fails electrically or mechanically, losing ability to detect pressure changes and report data to the PCM.
- 3
EGR or charge air system leaks
Leaks in the Exhaust Gas Recirculation system or turbocharger charge air piping allow false pressure readings or signal loss.
- 4
Corroded wiring or poor electrical connection
The sensor connector or wiring harness develops corrosion, loose terminals, or broken pins that interrupt the signal to the PCM.
How to Diagnose It
- 1
Check Blocked sensor tube or line — The pressure line running from the exhaust manifold or turbocharger to the sensor becomes clogged with soot or carbon deposits, blocking pressure signal transmission.
- 2
Check Defective exhaust pressure sensor — The sensor itself fails electrically or mechanically, losing ability to detect pressure changes and report data to the PCM.
- 3
Check EGR or charge air system leaks — Leaks in the Exhaust Gas Recirculation system or turbocharger charge air piping allow false pressure readings or signal loss.
- 4
Check Corroded wiring or poor electrical connection — The sensor connector or wiring harness develops corrosion, loose terminals, or broken pins that interrupt the signal to the PCM.
How to Fix It
- 1
Inspect and clean sensor tube
Locate the exhaust pressure sensor line running from the exhaust manifold or turbocharger and carefully remove any soot or carbon buildup blocking the tube. Replace the tube if it is cracked or damaged.
- 2
Replace exhaust pressure sensor
Disconnect the sensor connector, unbolt the sensor from its mounting location, and install a new OEM or quality replacement sensor. Reconnect wiring and clear the code.
- 3
Check EGR and charge air system for leaks
Inspect all EGR and turbocharger charge air lines, connections, and hoses for cracks, loose clamps, or separation. Repair or replace any components with visible damage and verify all connections are tight.
- 4
Repair wiring and electrical connections
Inspect the sensor connector and wiring harness for corrosion, loose pins, or damaged insulation. Clean corroded terminals with contact cleaner, reseat connectors firmly, or replace damaged wiring as needed.
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