P0487: EGR Throttle Control Circuit A/Open

Exhaust gas recirculation (EGR) routes part of the exhaust back into the intake to lower combustion temperature and NOx. The EGR throttle is a regulating flap ahead of the intake manifold on diesels: by closing partly it lowers manifold pressure below exhaust back pressure so that enough exhaust is recirculated, and it also helps filter regeneration and shuts off air at engine stop. It is usually a DC motor with position sensor. GM and Ford report this flap under P02E0 ff; no manufacturer document available to us uses this code. P0487 means its drive circuit is open or has a general circuit fault, detected by the output stage. The flap then stays open, so the EGR rate cannot be raised enough and filter regeneration may be blocked.

Symptoms

• Check engine light on
• Loss of power or limp mode possible
• Shaking when the engine is switched off
• Filter regeneration does not complete

Most likely causes

• Connector at the flap corroded or loose, wire open
• Flap actuator motor faulty (winding open)
• Pneumatic version: vacuum converter faulty
• Driver in the engine module

What to check, in order

Start with the simplest. You can tick off each step.

1. Check the connector and any vacuum hoses
2. Check the continuity of the wire between the component and the control module.
3. Use live data to compare the commanded opening with the actual opening
4. Clean the valve and passages if they are clogged with carbon
5. Test the actuator with the scanner
6. Replace the valve if it still does not follow the command after cleaning

Good to know

• Repair difficulty: medium
• It can trigger limp mode.
• It affects emissions.

What each character of P0487 means

• P: Powertrain: engine and transmission
• 0: Generic code: same on every make
• 4: Emissions
• 87: Specific fault in that system

Frequently asked questions

Can I keep driving with code P0487?

You can normally drive in moderation, but get it repaired soon: if the valve is stuck open, the engine may idle very poorly.

What causes code P0487?

The most common causes are: connector at the flap corroded or loose, wire open; flap actuator motor faulty (winding open); pneumatic version: vacuum converter faulty.

Related codes

• P0488EGR Throttle Control Circuit A Range/Performance
• P02E0Diesel Intake Air Flow A Control Circuit/Open
• P02E1Diesel Intake Air Flow A Control Performance
• P0403EGR A Control Circuit/Open
• P0401EGR A Flow Insufficient Detected

Sources

• law.cornell.edu: 13 CCR 1968.2
• ms-motorservice.com: throttle valves and regulating throttles
• patents.google.com: en

Values and procedures vary by manufacturer. If it affects brakes, steering, fuel or high voltage, see a professional. Updated: 2026-11-04. How we build these pages.