Cause
Open circuit in valve wiring
A break in the wiring to a solenoid-operated valve, so the module commands it and sees no current flow. The module cannot distinguish a broken wire from a burnt-out winding from an unplugged connector — all three read as an open circuit — and that is why this cause sits across valves in unrelated systems rather than belonging to any one of them.
The connector is the first thing to check and the likeliest finding. Valves in the emissions and recirculation systems sit on or near the engine and exhaust, where heat cycles harden the wire's insulation and vibration works terminals loose. A pin backed part-way out of its housing looks perfectly seated from outside and is one of the commonest causes here.
Where the harness breaks is predictable enough to inspect directly. Just behind the connector where the wire flexes, at a clip where the loom is held against something that moves, and anywhere the loom crosses a hot component. Test at the valve's connector rather than at the module — that splits the circuit in half in one measurement and tells you immediately whether you are looking for a wire or a winding, which is the difference between an hour with a loom and a five minute part swap.
Typically a moderate job.
Codes this can cause (5)
Codes where this is a likely explanation first, rather than merely a possible one.
- P2260 Secondary Air Injection System Control B Circuit High Likely for this code Moderate
- P2418 Evaporative Emission System Switching Valve Control Circuit Open Likely for this code Moderate
- P2420 Evaporative Emission System Switching Valve Control Circuit High Likely for this code Moderate
- P2425 Exhaust Gas Recirculation Cooling Valve Control Circuit Open Likely for this code Moderate
- P2427 Exhaust Gas Recirculation Cooling Valve Control Circuit High Likely for this code Moderate
Information, not instruction
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