P0487

What it means

P0487 means the engine control unit has detected an open circuit in the control circuit for the EGR throttle, a valve fitted in the intake path on some engines (mainly diesel) to help draw exhaust gas into the intake. The control unit monitors the actuator's driver circuit, and when it sees no current flow or an open-circuit condition it sets the code. Exact layout, connector location and actuator type depend on the model and engine.

Symptoms

• Engine warning light on
• Reduced power or the car going into limp mode on some models
• Rough idle or hesitation
• Increased exhaust smoke on some diesel engines
• Stalling or a shudder when switching the engine off on some models
• Failed emissions test

Possible causes

• Open circuit, chafed or broken wiring between the control unit and the EGR throttle actuatorlikely
• Corroded, loose or pushed-out pins in the actuator connectorlikely
• Faulty EGR throttle actuator with an open internal motor or solenoid windinglikely
• Missing or open supply or earth to the actuator, such as a blown fuse or faulty relay where fittedpossible
• Carbon build-up or a seized throttle plate overloading the actuator and damaging its drivepossible
• Fault inside the engine control unit's driver stagerare
• Outdated control unit software, only where the manufacturer has a documented fix for the modelrare

How to diagnose

1. Read all stored and pending codes and the freeze frame data, noting engine temperature, load and speed when the fault set, and check for related EGR or throttle codes.
2. Check for relevant technical service bulletins for the model and engine.
3. Visually inspect the actuator, its wiring and connector for heat damage, chafing, corrosion, oil or coolant contamination and loose fitting.
4. Check the fuse and any relay feeding the actuator, using the wiring diagram for the vehicle.
5. With the ignition on, use the scan tool's bidirectional test to command the EGR throttle and see whether it moves and whether the commanded and actual positions agree.
6. Back-probe the connector to check for supply, earth and the control signal, then test the wiring for continuity and shorts to earth or supply with the connector disconnected at both ends.
7. Measure the actuator's winding resistance against the manufacturer's specification, and check the throttle plate moves freely by hand if it is accessible.
8. After repair, clear the code and road test, rechecking that the code does not return and that commanded and actual positions match.

How to fix

• Repair or replace damaged wiring, with proper soldered or crimped and sealed joins, and secure the loom away from heat and abrasion.
• Clean, repair or replace corroded or damaged connector terminals and ensure the connector latches fully.
• Replace the EGR throttle actuator or valve assembly if its winding is open or it is mechanically seized.
• Replace a blown fuse or faulty relay and find out why it failed.
• Clean carbon from the throttle body and passages if sticking caused the fault, and fix the underlying cause of the contamination.
• Update the control unit software only if the manufacturer lists it as a fix, or repair or replace the control unit if testing proves its driver faulty.

Can I keep driving?

Nearby codes

• P0486GenericEGR Sensor B Circuit
• P0488GenericEGR Throttle Control Circuit A Range/Performance