P0A42 code meaning
Drive Motor A Position Sensor Circuit High
Powertrain system Generic code P0Axx codes Check engine light
What P0A42 means
P0A42 is the counterpart to P0A41: a resolver line of motor A reads above its allowed range. Typical triggers are a sine, cosine or excitation wire shorted to a supply voltage, or an open coil whose line is pulled up by the bias resistors of the input circuit, which drives the converter into clipping. Kia covers it in the same Optima Hybrid 2011-13 bulletin as P0A41: intermittent MIL or hybrid service lamp, fixed by inspecting the HPCU-to-motor sub-harness for internal shorts and pin fit. Bosch patents explain why clipping alone is not enough and how the line offset reveals a short to supply or an open line. P0A3F is the general circuit fault. Expect a warning lamp and reduced or no electric drive.
P0A42 at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modePossible
- Repair difficultyWorkshop only
- Typical labor1 to 8 hours
- Clears after repairWhen cleared with a scanner
Symptoms of P0A42
- Intermittent MIL or hybrid service lamp
- Electric drive disabled or vehicle not ready
- Reduced power until the fault clears
Common causes of P0A42
- Most likelyResolver wire shorted to a supply voltage inside the sub-harness (Kia Optima Hybrid)
- PossibleOpen sine or cosine line pulled high by the input circuit
- PossiblePoor pin fit or corrosion at the resolver connectors
- Less likelyFaulty resolver input stage in the motor control unit
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Drive motor a position sensorWiring harnessHybrid control module
What each part of P0A42 means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 0 | Generic code: it means the same on every make (SAE standard). |
| A | Area: hybrid propulsion. |
| 42 | The exact fault in that area. |
What to do next
- Note P0A42 and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about P0A42
What does P0A42 mean?
P0A42 means "Drive Motor A Position Sensor Circuit High". P0A42 is the counterpart to P0A41: a resolver line of motor A reads above its allowed range. It is a generic code, so it means the same on every make.
Is it safe to drive with P0A42?
Drive gently and only to a workshop. With P0A42 the car can go into limp mode (reduced power) to protect itself.
Will P0A42 fail an emissions test?
Yes, it can. P0A42 is emissions-related, so most inspection programs fail a car while it is stored or while the check engine light is on.
How hard is P0A42 to fix?
Difficulty: workshop only. A typical repair takes 1 to 8 hours of work. This is a job for a workshop.
Will P0A42 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.