What P06A6 means
The engine module feeds sensors from several regulated 5 V reference circuits; a short at one sensor pulls the whole circuit down, so all its sensors report at once – unplug them one by one to find the culprit.
How the engine computer detects it
P06A6 is the range/performance check of reference circuit A: the voltage is outside a narrow window without being split into low and high. Ford uses it: its 2012 and 2020–23 gasoline tables flag below 4.7 V or above 5.2 V for 0.5 s (Bosch modules), and the 2023 diesel below 4.7 V or above 5.3 V for 5 s, where supply 1 feeds the rail pressure and crankshaft sensors. In the Saab 9-4X the fuel pump control module uses it for its fuel pressure sensor supply. Expect fuel pressure or crankshaft codes and reduced power; Ford's low/high codes for circuit A are P0642/P0643.
Written from public technical sources and not yet checked by a mechanic. How we write these pages
Symptoms
- Check engine light
- Fuel pressure or crankshaft sensor codes as well
- Reduced power or starting problems
Common causes
- Short in the wire or sensor of a connected sensor Most likely
- Chafing or water in harness or connector Possible
- A connected sensor faulty internally Possible
- Module internal voltage regulator Less likely
How to diagnose P06A6
- Read every stored code with an OBD-II scanner. If misfire or fuel trim codes are there too, fix those first: they often cause this one.
- Inspect the parts involved: sensor reference voltage circuit, sensor wiring, engine control module.
- Work through the causes above from most to least likely, cheapest checks first.
- Clear the code and drive a full drive cycle to confirm the repair held.
Reading the code
- P
- Powertrain
- 0
- Generic (SAE) code
- 6
- Computer and output circuits
- A6
- Specific fault
Questions drivers ask
Can I drive with code P06A6?
Drive gently and only as far as you need to. The engine computer may limit power to protect the engine, so avoid highways and heavy traffic until it's fixed. If the check engine light starts flashing, pull over.
Will my car pass an emissions inspection with P06A6?
Probably not in states that test vehicles with an OBD-II scan: an emissions-related code that keeps the check engine light on is usually an automatic fail. Rules differ by state and county, so check yours.
This page is general information, not a substitute for a professional diagnosis. Repair costs are rough estimates for parts and labor and vary by vehicle and region.