P001A
A Camshaft Profile Control Circuit/Open Bank 1P001A is a generic OBD-II powertrain diagnostic trouble code: A Camshaft Profile Control Circuit/Open Bank 1. It is logged by the engine control unit when the ckp/cmp monitor detects that a specific fault threshold has been exceeded — typically resulting in the malfunction-indicator lamp (MIL / check-engine light) being illuminated.
What P001A means
P001A — A Camshaft Profile Control Circuit/Open (Bank 1) — is an electrical fault code indicating that the engine control module (ECM) has detected an open circuit condition in the control circuit for the "A" (intake) camshaft profile switching actuator on Bank 1. Unlike variable valve timing (VVT) codes which relate to cam position angle, camshaft profile control codes (P001x series) concern systems that physically switch between two discrete cam lobe profiles — such as Honda's VTEC, BMW's Valvetronic, or similar two-stage lift mechanisms — to alter valve lift and duration. The ECM drives an oil pressure solenoid or electromagnetic actuator to engage the high-lift profile at higher engine speeds or loads; when the commanded signal cannot complete its circuit back to ground (open condition), no current flows, the actuator cannot engage, and P001A is stored. The most common cause is a broken wire, corroded connector, or failed actuator coil. Because the engine is locked into the low-lift cam profile, performance above moderate load is significantly reduced and fuel economy suffers. While the vehicle can typically still be driven, sustained operation in this state is inadvisable as the ECM cannot optimise combustion efficiency.
Common causes
Most-frequently reported root causes when P001A is logged.
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1
Broken, chafed, or open-circuit wire in the camshaft profile control actuator harness
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2
Corroded, pushed-back, or moisture-contaminated actuator connector terminals
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3
Failed camshaft profile control actuator (solenoid coil open internally)
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4
Poor ground connection in the actuator circuit or at the engine block ground strap
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5
Damaged ECM output driver for the actuator control circuit
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6
Low or contaminated engine oil preventing hydraulic engagement of the profile switching mechanism
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7
Faulty camshaft position sensor providing incorrect feedback that triggers circuit monitoring faults
Symptoms drivers notice
How to diagnose P001A
A typical diagnostic flow when this code is present.
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1
Retrieve all codes; note whether P001A is the only fault or is accompanied by cam timing or oil pressure codes, as this guides whether the fault is purely electrical or also mechanical
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2
Visually trace the camshaft profile actuator wiring harness from the ECM connector to the actuator; look for chafed insulation near hot surfaces or sharp edges, and inspect all connectors for corrosion or spread terminals
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3
With the ignition on (engine off), measure voltage at the actuator connector; expected supply or reference voltage depends on the specific system — consult wiring diagrams
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4
Use a multimeter to perform a continuity test on each wire in the actuator circuit back to the ECM connector; an open will show infinite resistance
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5
Measure the actuator solenoid coil resistance; an open coil (infinite resistance) confirms internal actuator failure — compare against manufacturer specification
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6
Check engine oil level and condition; some profile-switching systems require adequate hydraulic pressure to function even if the electrical circuit is intact
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7
If wiring and actuator are confirmed good, check ECM connector pins for corrosion and verify ECM ground integrity before suspecting an ECM output driver fault
Related powertrain codes
- P000A — A Camshaft Position Slow Response Bank 1
- P000B — B Camshaft Position Slow Response Bank 1
- P000C — A Camshaft Position Slow Response Bank 2
- P000D — B Camshaft Position Slow Response Bank 2
- P0010 — A Camshaft Position Actuator Circuit (Bank 1)
- P0011 — A Camshaft Position - Timing Over-Advanced or System Performance (Bank 1)
Frequently asked questions
What does 'A' camshaft mean in P001A?
In SAE J1930 nomenclature, 'A' designates the intake camshaft (or left/front cam in some configurations). 'B' would be the exhaust camshaft. Bank 1 is the bank containing cylinder number 1.
What is camshaft profile control versus variable valve timing?
VVT (addressed by P001x timing codes) continuously varies the camshaft's rotational phase angle to optimise timing across all RPM ranges. Camshaft profile control (addressed by P001A/P001B) switches between two fixed cam lobe shapes — typically a low-lift quiet lobe and a high-lift performance lobe — at a specific RPM or load threshold.
Can I repair the wiring myself for P001A?
If you can locate and access the break, yes — a clean wire repair with proper heat-shrink solder connectors is a valid fix. The challenge is finding the break, which can be hidden inside the loom. A wiring diagram and a multimeter continuity test are essential.
Will P001A cause the car to fail emissions?
Yes — with the MIL illuminated, most jurisdictions will fail a vehicle at an OBD-II emissions inspection. Beyond that, being locked into the low-lift cam profile increases fuel consumption and emissions at higher loads.
Disabling P001A in software
RaceTune can permanently disable P001A — and any other OBD-II diagnostic trouble code — on every ECU family we support. The monitor is disabled inside the ECU itself, so the fault stops being logged: the warning light stays off and the engine never enters limp mode for this code. The change is tied to your exact software version.
ECU families we can disable P001A on
We hold the DaVinci A2L disable definitions for these families, so the exact P001A path and mask addresses are mapped. verified marks a confirmed disable definition. We support many more — upload your file and our identifier will match it automatically.
- Bosch MG1CP002 verified
Software modifications affect emissions compliance and are not road-legal in many jurisdictions. RaceTune service files are intended for motorsport, off-road, and export use.
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