U011A code meaning
Lost Communication With Exhaust Gas Sensor Module A
Network system Generic code U01xx codes Check engine light
What U011A means
U011A appears when the engine controller loses exhaust gas sensor module A, the electronics that heat and evaluate a wide-band oxygen probe (or a similar exhaust sensor) and send the result as bus data instead of analogue signals. Chrysler's bulletin 25-002-14, which replaces 25-003-13 and 25-004-13, lists it for 2010–2012 Ram 2500/3500 pickups with the 6.7 L Cummins among oxygen-sensor faults; the prescribed fix is an overlay harness with new connectors at the sensor module before any part is changed. Module B has U016D, invalid data from A is U041B. Since the controller loses the oxygen value it needs for combustion and aftertreatment control, the MIL lights and soot-model or regeneration functions may be restricted.
U011A at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modeNot expected
- Repair difficultyMedium
- Typical labor1 to 4 hours
- Clears after repairAfter a drive cycle
Symptoms of U011A
- MIL on
- Further oxygen-sensor codes stored
- Particulate filter regeneration restricted
Common causes of U011A
- Most likelyHeat-stressed wiring or poor terminal contact at the sensor module connector
- PossibleSensor module without power or ground
- Less likelyExhaust gas sensor module internally faulty
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Exhaust gas sensor module aCAN bus wiring
What each part of U011A means
| U | Network system: communication between the control modules (CAN bus). |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 1A | The exact fault in that area. |
What to do next
- Note U011A 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 U011A
What does U011A mean?
U011A means "Lost Communication With Exhaust Gas Sensor Module A". U011A appears when the engine controller loses exhaust gas sensor module A, the electronics that heat and evaluate a wide-band oxygen probe (or a similar exhaust sensor) and send the result as bus data instead of analogue signals. It is a generic code, so it means the same on every make.
Is it safe to drive with U011A?
Usually yes, for a short time, if the check engine light is steady and the car drives normally. If the light flashes or the car runs badly, stop and have it checked.
Will U011A fail an emissions test?
Yes, it can. U011A 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 U011A to fix?
Difficulty: medium. A typical repair takes 1 to 4 hours of work. This is a job for a workshop.
Will U011A clear itself after the repair?
After the repair the car has to complete a drive cycle (a mix of city and highway driving) before the test runs again. Until then the readiness monitor shows "not ready", which can fail an inspection.