Code P0470: exhaust pressure sensor: circuit fault

Original definition (SAE J2012): Exhaust Pressure Sensor "A" Circuit^[1][2][3]

• P0470Exhaust pressure sensor "A" circuit (sensor or circuit fault).
• P0472Exhaust pressure sensor "A" circuit: low signal. TaT explains that the ECU detects a signal or supply voltage lower than expected, which usually indicates a short to ground, an open circuit or a faulty sensor.^[3][8][9]
• P0473Exhaust pressure sensor "A" circuit: high signal. TaT explains that the ECU detects a signal or supply voltage higher than expected, which usually indicates a short to voltage, an open circuit or a faulty sensor.^[3][10][11]

1. 1Faulty exhaust pressure sensor.^[5][12]
2. 2Blocked or damaged sensor intake tube or pipe. Autodoc Club cites it, and PartsAvatar, on its P0471 page, speaks of a blockage in the tube running from the exhaust manifold to the sensor. Autobiz points out that the most common problem is carbon built up in the hollow bolt (banjo) or in the intake tube.^[4][5][12]
3. 3Damaged, corroded or loose sensor wiring or connectors, or a poor earth connection. On the low and high signal codes, TaT speaks of a short to ground or to voltage, an open circuit or a faulty sensor.^[5][8][10]
4. 4Blocked EGR valve or EGR passages (Autodoc Club) or, according to PartsAvatar, an EGR system problem.^[5][12]
5. 5Dirty or blocked exhaust manifold.^[5]
6. 6Faulty ECU software or a fault in the ECU itself, an uncommon case.^[5][12]

• Engine warning light on. Autodoc Club cites it on the pages for the sibling codes P0472 and P0473.^[9][11]Engine warning light: faults that cause it
• Less engine power and poorer acceleration.^[5][9][11]Less power: faults that cause it
• Unstable idle.^[5][9][11]Vibrations: faults that cause it
• More emissions and black smoke.^[5]Black smoke: faults that cause it
• Noticeably higher fuel consumption.^[5][9]Uses more fuel: faults that cause it
• Hard starting when cold or prolonged warm-up.^[5][9]Hard to start: faults that cause it
• On P0473, Autodoc Club adds that the car may go into limp mode.^[11]Limp mode: faults that cause it
• Unusual knocking noises or uneven engine running.^[5]
• On diesels, particulate filter regeneration problems (cited by Autodoc Club for P0473).^[11]
• Other exhaust or turbo codes may also be stored.^[12]

1. 1Read the codes with the scan tool and also check the other exhaust, turbo and EGR codes, because they often appear together.^[12]
2. 2Find out which sensor the code monitors on your engine: the manifold pressure sensor or, on many VW Group diesels, the particulate filter one. The manufacturer's diagram shows it, and these are parts that are rarely interchangeable.^[4][6]
3. 3Inspect the sensor wiring and connectors for damage or corrosion.^[12]
4. 4Check the tube that carries exhaust pressure to the sensor. If it is blocked by carbon, Autobiz suggests cleaning it by heating the pipe or hollow bolt with an induction heater while blowing compressed air from the disconnected sensor side.^[4][12]
5. 5Check the EGR system and the exhaust manifold, which Autodoc Club and PartsAvatar cite among the causes.^[5][12]
6. 6If the code is for low or high signal, look for what TaT gives as the typical cause: a short to ground or to voltage, an open circuit or a faulty sensor.^[8][10]
7. 7Replace the sensor only if the earlier checks point to it.^[12]

• Turbo

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• EGR valve

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• Particulate filter

  • Buy part at Autodoc (affiliate link, opens in a new tab)