P0487 Open circuit of the throttle valve control of the exhaust gas recirculation system

OBD-II Trouble Code - P0487 - Data Sheet

P0487 - Exhaust Gas Recirculation (EGR) "A" Throttle Control Circuit Open

Code P0487 indicates a malfunction in the exhaust gas recirculation (EGR) system. This code may also be present along with P0409.

What does trouble code P0487 mean?

This Generic Transmission / Engine DTC usually applies to diesel engines built after 2004, including but not limited to certain Ford, Dodge, GM, Mercedes, Mitsubishi, Nissan, Suzuki, and VW vehicles.

This valve is located between the intake manifold and the air filter, like a throttle body. It is used to create a small vacuum that will draw exhaust gases into the intake manifold.

The powertrain control module (PCM) tells the exhaust gas recirculation (EGR) throttle valve where it is. This code looks at the voltage signals from the EGR throttle control valve to determine if they are correct based on input to the PCM. This code informs you about a malfunction of the electrical circuit.

Troubleshooting steps may vary depending on the manufacturer, type of EGR throttle valve and wire colors.

Symptoms

There are very few symptoms associated with a P0487 code other than an illuminated Check Engine light. However, some drivers may notice reduced fuel consumption, fluctuating acceleration, and rougher-than-normal engine performance.

Symptoms of a P0487 engine code may include:

• Malfunction Indicator Lamp (MIL) illuminated
• Longer than usual active post-treatment regeneration time (it takes longer for the exhaust system to heat up and burn off the soot accumulated inside the DPF / catalytic converter)

Possible Causes of Code P0487

Usually the reason for installing this code is:

• Open in signal circuit between EGR throttle valve and PCM
• A short to voltage in the exhaust gas recirculation throttle signal circuit.
• A short to ground in the exhaust gas recirculation throttle signal circuit.
• Exhaust gas recirculation throttle valve defective - internal short circuit
• Failed PCM – Unlikely
• Clogged or blocked passages in the EGR valve
• EGR valve failure
• Faulty MAP sensor
• Faulty EGR control solenoid
• damaged or broken vacuum line
• Blocked DPFE sensor passages (mostly on Ford vehicles)

Diagnostic and repair procedures

A good starting point is always to check the Technical Service Bulletins (TSB) for your particular vehicle. Your problem may be a known issue with a known manufacturer-released fix and could save you time and money while troubleshooting.

Then find the EGR throttle control valve on your specific vehicle. This valve is located between the intake manifold and the air filter, just like a throttle body. Once detected, visually inspect the connectors and wiring. Look for scratches, scuffs, exposed wires, burn marks, or molten plastic. Disconnect the connectors and carefully inspect the terminals (metal parts) inside the connectors. See if they look burnt or have a green tint indicating corrosion. If you need to clean the terminals, use an electrical contact cleaner and a plastic bristle brush. Allow to dry and apply dielectric silicone grease where the terminals touch.

If you have a scan tool, clear the diagnostic trouble codes from memory and see if the code returns. If this is not the case, then there is most likely a connection problem.

If the P0487 code does return, we will need to check the EGR throttle valve and related circuits. Typically 3 or 4 wires are connected to the EGR throttle valve. Disconnect the harness from the EGR throttle valve. Use a digital volt ohmmeter (DVOM) to check the EGR throttle control valve signal circuit (red wire to valve signal circuit, black wire to good ground). If there is no 5 volt on the valve, or if you see 12 volts on the valve, repair the wiring from the PCM to the valve, or possibly a faulty PCM.

If normal, make sure you have a good ground at the EGR throttle valve. Connect a test lamp to the 12V battery positive (red terminal) and touch the other end of the test lamp to the ground circuit that leads to the EGR throttle valve circuit ground. If the test lamp does not light up, it indicates a faulty circuit. If it illuminates, wiggle the wiring harness going to the EGR throttle valve to see if the test lamp blinks, indicating an intermittent connection.

If all previous tests pass and you keep getting P0487, it will most likely indicate a failed EGR throttle control valve, although the failed PCM cannot be ruled out until the EGR throttle control valve is replaced.

Common Mistakes When Diagnosing Code P0487

The single most common error in diagnosing code P0487 is to immediately assume that the problem is with the EGR valve. While it's not uncommon for the valve itself to fail, it's actually more often a problem with a damaged vacuum line or a faulty solenoid. Replacing the valve not only won't fix the problem, but these parts are actually more expensive than many other repairs.

How serious is the P0487 code?

Code P0487 may not greatly affect your ability to drive, but it can be a problem. It will also prevent your vehicle from passing emission tests and should be repaired as soon as possible.

What repairs can fix code P0487?

A number of possible repairs can be used to fix code P0487, including the following:

• Replacement of damaged vacuum lines
• Replacing a failed solenoid
• Replacement EGR valve
• EGR channel cleaning

Additional comments to consider regarding code P0487

Your car's exhaust gas recirculation system is an important part of both your vehicle's emissions system and your vehicle's fuel system. Exhaust gases must be re-burned to improve fuel economy and reduce the amount of fumes emitted to the atmosphere.

What is P0487 Engine Code [Quick Guide]

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