Guide To P0477 OBD Error Code Solutions

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Error Code P0477? OBD? Exhaust Pressure Control Valve? Lost in too many complex words? Keep Calm! At Parts Avatar, we’ve got our back. Here's a brief to make things simpler for you. This generic diagnostic trouble code P0477 is primarily concerned with the Exhaust Pressure Control Valve Low. The exhaust back pressure valve is in charge of controlling the exhaust back pressure. The circuit installed connecting to the valve obtains the data regarding the pressure in volts and transmits this data to the PCM. If the voltage recorded by the PCM comes lower than the voltage required as per the manufacturer’s specifications, it stores the P0477 code. Got it? No? We have more on the go!

The detection of an abnormally low voltage from the exhaust back pressure control valve circuit by the PCM signifies the Error code P0477. This code may be stored along with the other codes that are similarly relate the exhaust back pressure control system, like the code P0478 and P0479 code.

What causes this problem with the Exhaust Pressure Control Valve "A" Low

• Insufficient power in the power supply circuit between the exhaust pressure control solenoid and the PCM (powertrain control module).
• A disconnect in the power supply circuit between the exhaust pressure control solenoid and the PCM.
• Short to the ground in the power supply circuit to the exhaust pressure control solenoid.
• Defective Exhaust Pressure Control Relay.
• A possible fault in the Exhaust Pressure Control Solenoid or a failure in the PCM (that is quite unlikely to happen).

1. Indicator Lamp - Having problems with the Indicator lamp? Don’t you worry, Parts Avatar has it all. A faulty Indicator Lamp could end up being the root cause behind the Error code P0477.
2. Exhaust Back Pressure Sensor - The Exhaust Back Pressure Sensor or the EBP sensor is the variable capacitance sensor that controls the pressure so that the PCM can regulate the Exhaust Back Pressure Regulator (EPR) when required. So a distorted one can always lead to complications. Why not get it changed?
3. Powertrain Control Module (PCM) - abbreviated PCM; this is an integral control unit. So a damaged one should be changed immediately.
4. Exhaust Back Pressure Valve Solenoids - Facing the error code P0477? An inferior quality Exhaust Back Pressure Valve can always be hazardous for the system also it is one of the major causes behind the occurring of the error code P0477. Tune into Parts Avatar for supreme quality Exhaust Back Pressure Valve Solenoids at economical prices.

Interested in knowing the symptoms of the OBD Error Code P0477? If yes, then you have arrived at the right place. We at Parts Avatar have listed here a few common symptoms associated with Exhaust Pressure Control Valve “A” Low problem

• The light appearing on of the Malfunction Indicator Lamp (MIL).
• Insufficient power.
• Inadequacy in the Engine breaks.
• The cold engine taking longer than normal to warm up.

Wishing to combat the Error Code P0477? Here listed are a few steps that need to be followed to avoid or overcome the OBD Error Code P0477-

• Mending and repairing the clogged back-pressure tube.
• Repairing, cleansing and replacement of the Exhaust back pressure sensor.
• The exhaust pressure back valve should be repaired and changed.
• Repairing the shortened or disconnected exhaust pressure valve harness.
• Keeping a check on the electrical connection in the exhaust back pressure valve circuit. Repairing or replacing it if required.
• Changing the distorted exhaust back pressure valve solenoids.
• Mending or altering the damaged the electrical components, such as wires and connectors.
• Restoring the faulty PCM. (possible in certain cases).
• Repairing and restoring faulty EBP, EOT or IOT sensors.
• Diagnosing and mending the problems related to other codes in the PCM relating to the back-exhaust pressure system.

Wondering on how are you going to diagnose the Error Code P0477? Parts Avatar to the rescue! We not only believe in providing our customers with finest quality products but also ensure equipping them with all the information we got. Here are a few steps that can make the detection and diagnosis easy.

• The exhaust back pressure system using a variable capacitance sensor monitors the exhaust back pressure and the input data to the PCM.
• After examining and inspecting from various other engine and drivability sensors the PCM calculates the required amount of exhaust back pressure.
• Exhaust back pressure is controlled through using the exhaust back pressure regulator vent control solenoid.
• The PCM then transmits the signals to the solenoid, which in return opens and closes, letting the gas back pressure to increase or decrease as required.
• The confirmed exhaust back pressure sensor voltage (varying between manufactures’) is then compared to the manufacturer's recommended exhaust back pressure sensor voltage.
• If the readings recorded fail to match, a code is stored and the exhaust back system is disabled. if there are any other turbocharger or exhaust codes, they should be diagnosed and repaired before to overcome this Error Code and repairing it.
• The tools that prove to be quite helpful with the diagnoses are a Scanner (or a code reader) and the digital volt/ohmmeter.
• There might be a requirement of several tools to diagnose, if no exhaust leaks are detected.
• An appropriate Scanner (or a code reader), a digital volt/ohmmeter, and a manufacturer’s service manual are all essential in order to undertake a successful diagnosis.

Common Mistakes When Diagnosing the P0477 Code

Because of sharing notable similarities with other codes, the diagnosis of the Error Code P0477 at times, may end up being a strenuous task. So here listed are a few common mistakes which might act as an obstacle while diagnosing the code.

Due to similarities with other codes, it becomes quite possible to and usual to misdiagnose the code as having something to do with the exhaust gas recirculation system. Although, both these systems are located nearby but are diagnosed completely in a different way.

Also, other generally made mistake is when people forget to clear all the codes and perform a retest of the system after each potential repair. This step is highly important as it helps in cutting down the root cause until the malfunction is found and repaired.

P0475 - Exhaust Pressure Control Valve "A"

P0478 - Exhaust Pressure Control Valve "A" High