What Does P0487 Mean?
The EGR throttle control circuit 'A' has an open circuit condition. The EGR throttle (a separate throttle valve used in some diesel and advanced gasoline engines to control intake manifold vacuum for EGR flow) is not receiving its control signal. The driver may notice increased emissions, rough idle, or reduced engine performance due to uncontrolled EGR flow.
Common Causes
30%
Broken or disconnected wiring to the EGR throttle control valve actuator
28%
EGR throttle control valve actuator motor open circuit (internal winding break)
22%
Corroded or damaged connector preventing electrical contact
12%
Blown fuse in the EGR throttle power supply circuit
8%
ECM output driver failure for the EGR throttle control
Diagnostic Steps
1
Locate the EGR throttle control valve and verify the connector is fully seated and locked. Disconnect and inspect for bent, corroded, or recessed pins.
2
Measure the actuator motor resistance across the motor terminals — typically 2-20 ohms depending on the design. An open reading (OL/infinite) confirms an internal motor winding break.
3
Check for 12V power supply at the valve connector with KOEO (if applicable). Some systems provide constant power through a fuse — verify the fuse is intact.
4
Test the ECM control signal at the valve connector using a noid light or test light. The ECM should pulse the ground circuit to control the motor. No signal points to an open wire or ECM driver fault.
5
Trace the harness from the valve to the ECM, checking for broken wires, especially at flex points, grommets, and areas near moving engine components where wires fatigue over time.
Estimated Repair Cost
$150 - $700
Parts + labor, varies by vehicle and location
The EGR throttle control circuit 'A' has an open circuit condition. The EGR throttle (a separate throttle valve used in some diesel and advanced gasoline engines to control intake manifold vacuum for EGR flow) is not receiving its control signal. The driver may notice increased emissions, rough idle...
The most common cause of P0487 (Exhaust Gas Recirculation Throttle Control Circuit "A" Open) is: Broken or disconnected wiring to the EGR throttle control valve actuator
Typical repair costs for P0487 range from $150 to $700, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Safe to drive short distances. Without EGR throttle control, emissions may increase and idle quality may suffer. On diesel engines, this can also affect DPF regeneration. Schedule repair within 1-2 weeks.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P0487 to identify the root cause.
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Quick Info
Category
Powertrain
System
EGR / Emissions System
Difficulty
Type
Generic (SAE)
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