P0470 – Exhaust Pressure Sensor Malfunction

Urgency and Driving Considerations

Code P0470 indicates a problem with the exhaust pressure sensor circuit. While not typically an immediate safety hazard, driving with this fault can lead to reduced engine performance, increased emissions, and potential long-term engine damage. It's advisable to diagnose and repair the issue promptly, but in most cases it is safe to drive to a repair shop or dealership rather than stopping immediately.

Code Details and Applicability

P0470 is a generic powertrain code, meaning it has the same definition for all vehicles equipped with OBD-II, regardless of make or model. It specifically indicates that the powertrain control module (PCM) has detected a malfunction with the exhaust pressure sensor "A" circuit.

The exhaust pressure sensor, also known as the exhaust backpressure sensor, measures the pressure in the exhaust system. It sends this data to the PCM to regulate emissions control systems and turbocharger operation (if equipped).

Common Causes

Potential causes of a P0470 code include:

• Blockage in the tube connecting the exhaust manifold to the pressure sensor
• Leaks in the exhaust pressure sensor tube or exhaust manifold
• Faulty exhaust pressure sensor
• Damaged wiring or poor electrical connections in the sensor circuit
• Issues with the PCM

Diagnostic Steps

1. Clear the code and test drive to see if it returns, indicating an ongoing issue.
2. Visually inspect the wiring and connectors for damage, corrosion, or loose connections.
3. Check for blockages or leaks in the tube connecting the exhaust manifold to the sensor.
4. Test the exhaust pressure sensor itself using a digital multimeter or oscilloscope. Replace if faulty.
5. Verify PCM operation and consider reprogramming or replacement if other causes are ruled out.

Repair Solutions and Costs

Common repairs for a P0470 code include:

• Replacing the exhaust pressure sensor: $150-300 (€130-260)
• Cleaning or replacing the sensor tube: $50-100 (€45-90)
• Repairing damaged wiring: $100-200 (€90-175)
• Reflashing or replacing the PCM: $500-1000 (€450-900)

Parts costs will vary by vehicle make and model. Labor costs are estimated at $75-150 (€65-130) per hour.

Prevention and Related Issues

Proper maintenance of the exhaust system and prompt repairs can help prevent P0470 faults. This code may appear in conjunction with related codes P0471 (exhaust pressure sensor range/performance), P0472 (low input), P0473 (high input), and P0474 (intermittent input).

When diagnosing, be sure to check for other codes that could point to underlying issues like exhaust leaks or turbocharger faults. The exhaust pressure sensor tube is prone to carbon buildup, so regular cleaning every 30,000 miles (48,000 km) is advised.

Hopefully this in-depth look at code P0470 helps your readers better understand this exhaust system fault. As always, proper diagnosis is key to an effective and lasting repair.

Frequently Asked Questions About P0470

What does the OBD-II code P0470 mean?

Code P0470 indicates that the powertrain control module (PCM) has detected a malfunction with the exhaust pressure sensor "A" circuit. This sensor measures exhaust backpressure and sends the data to the PCM to regulate emissions systems and turbocharger operation.

Is it safe to drive with a P0470 code?

While a P0470 code does not typically present an immediate safety hazard, driving with this fault can lead to reduced engine performance, increased emissions, and potential long-term engine damage. It's best to diagnose and repair the issue promptly.

What are common symptoms of a P0470 code?

Symptoms may include:

• Illuminated check engine light
• Reduced engine performance or lack of power
• Increased fuel consumption
• Difficulty with emissions testing

What causes a P0470 code?

Common causes include:

• Faulty exhaust pressure sensor
• Blockage or leak in the sensor tube connecting to the exhaust manifold
• Damaged wiring or poor electrical connections in the sensor circuit
• Issues with the PCM

How do you diagnose a P0470 code?

Diagnostic steps typically involve:

1. Checking for related technical service bulletins (TSBs)
2. Visually inspecting wiring, connectors, and the exhaust system
3. Testing the exhaust pressure sensor circuit with a multimeter
4. Assessing sensor functionality by comparing its data to other sensors
5. Verifying PCM operation and programming

What parts may need to be replaced to fix a P0470 code?

Repairs often involve replacing the exhaust pressure sensor, cleaning or replacing the sensor tube, repairing wiring, or in some cases, replacing or reprogramming the PCM.

How much does it cost to repair a P0470 code?

Repair costs can range from $150-300 for a sensor replacement to $500-1000 for PCM replacement or reprogramming, plus $75-150 per hour in labor. Exact costs depend on the vehicle make and model.

Can a P0470 code cause a vehicle to fail an emissions test?

Yes, a faulty exhaust pressure sensor can lead to increased vehicle emissions and may cause a failure of emissions testing until repaired.

What other codes may appear along with P0470?

Related codes can include P0471 (exhaust pressure sensor range/performance), P0472 (low input), P0473 (high input), and P0474 (intermittent input).

How often should the exhaust pressure sensor tube be cleaned to prevent a P0470 code?

As the sensor tube is prone to carbon buildup, regular cleaning every 30,000 miles (48,000 km) is recommended as preventative maintenance.

Can a P0470 code affect turbocharger operation?

Yes, the exhaust pressure sensor provides data to the PCM to regulate turbocharger boost pressure. A faulty sensor can lead to incorrect turbo operation.

Is the exhaust pressure sensor the same as an exhaust back pressure sensor?

Yes, the terms exhaust pressure sensor and exhaust back pressure sensor refer to the same component.

Where is the exhaust pressure sensor located?

The sensor is typically located on the exhaust manifold or exhaust pipe, with a tube connecting it to the manifold to measure backpressure.

Can a clogged catalytic converter cause a P0470 code?

While a clogged catalytic converter can cause increased exhaust backpressure, it would more likely trigger a different code such as P0420 or P0421 related to catalyst efficiency. However, the root cause of a P0470 code should still be properly diagnosed.

How does the exhaust pressure sensor work?

The sensor contains a diaphragm that flexes based on exhaust backpressure. This movement is converted into an electrical signal sent to the PCM. The PCM compares this pressure data to other sensors like the MAP and BARO to regulate engine operation.

Can a P0470 code cause limp mode?

In some cases, a P0470 code may trigger a failsafe or "limp home" mode to protect the engine from potential damage due to incorrect sensor data. This can limit engine RPM and performance until the issue is addressed.

Will disconnecting the battery clear a P0470 code?

Disconnecting the battery may temporarily clear the code, but it will likely return if the underlying issue is not repaired. Proper diagnosis and repair are needed to resolve the problem.

Can a P0470 code be caused by a vacuum leak?

While a vacuum leak would more commonly trigger a different code like P0171 or P0174, it could potentially affect exhaust backpressure readings if severe. Proper diagnosis is key to determining the actual cause.

How do you test an exhaust pressure sensor?

The sensor can be tested with a multimeter or oscilloscope at the sensor connector. With the key on, engine off (KOEO), you should see a voltage signal that changes as you apply pressure or vacuum to the sensor. Refer to manufacturer specs for the expected voltage range.

What is the difference between an exhaust pressure sensor and an exhaust gas temperature sensor?

The exhaust pressure sensor measures exhaust backpressure, while the exhaust gas temperature sensor measures the temperature of the exhaust gases. They are separate sensors with distinct functions.

Hopefully this FAQ has provided some helpful information on understanding, diagnosing, and repairing an OBD-II P0470 code for an exhaust pressure sensor malfunction. As always, proper troubleshooting is essential for an accurate and lasting repair.