What does it mean?
P1262 is a Powertrain (engine, transmission, fuel system) fault code. It indicates: High Voltage Circuit Fault – Cylinders 2, 3, 5, and 8 .
Symptoms
- The MIL is on, sometimes flashing under load
- Heavy misfire from more than one cylinder at once and a very rough idle
- Difficult starting, long cranking or no start when the whole group is dead
- Loss of power, vibration through the body and jerky acceleration
- Raw fuel smell from the tailpipe and increased consumption
- Possible overheating of the catalytic converter after prolonged driving
Likely causes
- Feed wire for the group shorted to a driver wire or to ground inside the loom
- Injector harness rubbed through on a bracket, manifold edge or engine cover stud
- Corrosion or water in the group connector after a leak or a pressure wash
- One injector in the group with a shorted or partially shorted winding
- Burnt terminals at the module connector for that injector group
- Weak supply or a corroded shared ground for the group
- Failed module driver stage confirmed only after the harness tests clean
How to fix it
- Read misfire data and confirm the affected cylinders match this injector group
- Inspect the injector loom and connectors in that group for chafe points, melted insulation and moisture
- Measure each injector winding resistance with the connectors off and compare the four readings
- Test for a short between the feed wire and each driver wire, and for insulation to ground
- Reconnect injectors individually while monitoring the circuit to identify the faulty unit
- Inspect the module connector for burnt or spread terminals before considering the module itself
- Replace the faulty injector or repair the wiring, then verify balanced cylinder contribution and no return of the code after a road test