CUSTOMER CONCERN After climate-control-head replacement, A/C faults report no basic setting, compressor first run-in not completed, and control module not coded. CAUSE The replacement Automatic Temperature Control head had not been coded to the vehicle and the electric A/C compressor first-run-in routine had not been completed. CORRECTION Code the Automatic Temperature Control head using ODIS Software Version Management, perform basic settings and the compressor first-run-in

CUSTOMER CONCERN Intermittent no-start condition with Check Hybrid System warning and generator-control DTC P0A1A-151. CAUSE Substitution with a known-good inverter/converter assembly eliminated the fault, confirming an internal inverter/converter failure. CORRECTION Remove and replace the inverter/converter assembly, clear DTC P0A1A-151, and program the MG ECU and power-management ECU as specified by campaign E0E before verifying ready-mode operation.

CUSTOMER CONCERN Vehicle will not enter ready mode after an oil change and repeated attempts to reset the maintenance reminder; the combination meter illuminates but the brake warning remains on. CAUSE The 12-volt battery discharged below the level needed to power the hybrid control system during the extended reminder-reset attempts. CORRECTION Remove and replace the failed 12-volt battery and verify the Prius enters ready mode and the maintenance reminder resets normally.

CUSTOMER CONCERN Smart-key touch unlock does not operate and the vehicle will not start normally with the key present. CAUSE The smart-key system cancel function had been switched on, disabling passive-entry and normal smart-key starting. CORRECTION Enable the smart-key system through the cancel-function setting, perform the scan-tool smart-key location test, and verify passive entry and ready-mode operation.

CUSTOMER CONCERN After left-rear caliper and brake-hose replacement, C1203, C1345, and C1451 remain stored. CAUSE Air remained in the hydraulic brake system, preventing the linear-solenoid valve offset calibration from completing. CORRECTION Perform the scan-tool brake bleeding procedure until all air is removed, then perform the linear-solenoid valve offset calibration, clear DTCs, and verify brake operation.

CUSTOMER CONCERN Brake-system warning remains after collision repair and C1253 is stored. CAUSE Accumulator-pressure data rose to 3.7 volts while the pump ran, then continuously dropped to 3.1 volts and restarted the pump, confirming the ABS pump could not maintain hydraulic pressure. CORRECTION Remove and replace the ABS pump motor assembly, clear DTC C1253, and verify accumulator pressure and brake-assist operation.

CUSTOMER CONCERN A second intelligent key will not register even though the original key starts the vehicle normally. CAUSE The initial scan tool could not complete the immobilizer registration routine; the vehicle accepted programming with a capable scan tool. CORRECTION Perform intelligent-key and immobilizer registration with a compatible scan tool and verify both keys start the vehicle.

CUSTOMER CONCERN After rear brake service, the brake warning flashes, the right-rear parking brake will not apply, and C2005:74 is stored. CAUSE Confirmed failed right electric parking-brake actuator motor. CORRECTION Remove and replace the right electric parking-brake actuator motor, complete parking-brake service-mode procedures, clear DTCs, and verify parking-brake operation.

CUSTOMER CONCERN ABS and traction-control warning lights are on with a left-front wheel-speed fault. CAUSE The left-front wheel-speed sensor and its wiring tested functional. Inspection through the steering-knuckle opening found the wheel-bearing encoder ring missing. CORRECTION Remove and replace the left-front wheel bearing, clear the ABS fault, and verify wheel-speed signal and ABS operation.

CUSTOMER CONCERN Brake warning instructs the driver not to drive; the brake pedal vibrates and the hydraulic pump runs during application, with U0129 and C1800 stored. CAUSE Confirmed failed Electronic Stability Control module causing loss of brake-system communication and an Active Hydraulic Booster CAN timeout. CORRECTION Remove and replace the Electronic Stability Control module, clear DTCs, and verify brake-assist, CAN communication, and warning-lamp operation.

CUSTOMER CONCERN Hybrid starter-generator locks while turning and damages the drive belt. CAUSE Confirmed seized hybrid starter-generator pulley/rotor assembly. CORRECTION Remove and replace the hybrid starter-generator and damaged belt, then verify the generator rotates freely and the hybrid drive system operates normally.

CUSTOMER CONCERN A/C compressor is inoperative with no stored codes; scan data continues to show the A/C switch off. CAUSE Confirmed failed air-conditioning control panel. CORRECTION Remove and replace the A/C control panel and verify the compressor command and cooling operation.

CUSTOMER CONCERN Engine misfires with no compression on cylinder 3, no oil showing on the dipstick, multiple misfire codes, P1268, P128A, and P2646. CAUSE Compression testing confirmed internal engine and valve damage: cylinders 2 and 3 had no compression and cylinder 4 was also low. CORRECTION Remove and replace the damaged engine assembly, correct the oil level, clear DTCs, and verify compression and engine operation.

CUSTOMER CONCERN IMA warning illuminates intermittently and P15C4:03 indicates auto idle-stop is disabled. CAUSE B1227 identified an open outside-air-temperature sensor circuit. The sensor tested good, and inspection found chewed wiring in the engine compartment affecting the temperature-sensor and right-front lamp circuits. CORRECTION Repair the damaged outside-air-temperature sensor and right-front lamp wiring, clear DTCs, and verify IMA auto-stop and lamp operation.

CUSTOMER CONCERN Engine cranks but will not start; spark, injector pulse, and scan-tool communication are all absent, and relays may buzz in the underhood fuse box. CAUSE Confirmed poor connection at engine ground G101 on the driver side of the cylinder head after engine replacement. CORRECTION Clean and secure ground G101, repair the ground connection as needed, and verify spark, injector pulse, scan communication, and engine starting operation.

CUSTOMER CONCERN TPMS warning remains on, none of the tire-pressure sensors will train, and both keyless-entry transmitters are inoperative. CAUSE Confirmed failed Radio Transceiver Module, which supports both TPMS sensor reception and keyless-entry operation. CORRECTION Remove and replace the Radio Transceiver Module, perform the required TPMS sensor training, and verify TPMS and keyless-entry operation.

CUSTOMER CONCERN Electric power steering is inoperative and the PSCM stores DTCs C102D and C200D:49 immediately after clearing. CAUSE The steering gear had excessive internal friction and an electronic failure of the internal motor-rotation-angle sensor; neither fault is serviceable separately from the gear/PSCM assembly. CORRECTION Remove and replace the power steering gear/PSCM assembly, program the PSCM to the vehicle, clear C102D and C200D:49, and verify electric power-st

CUSTOMER CONCERN The malfunction indicator lamp is on with DTC P0C32, and the hybrid battery-pack cooling fan is inoperative even though it had previously been replaced. CAUSE The G14 hybrid battery-pack cooling fan motor failed again; the power, ground and variable command circuits tested correctly but the fan did not run. CORRECTION Remove and replace the failed G14 hybrid battery-pack cooling fan, clear P0C32, command the fan through its speed range, and verify battery-coo

CUSTOMER CONCERN The engine misfires on cylinders 1 and 2 with DTCs P0301 and P0302, and the driveline produces a severe chattering noise. CAUSE The confirmed repair identified a failed cylinder-head gasket; coolant loss after sitting and a startup misfire supported coolant entering a cylinder. CORRECTION Remove and replace the failed cylinder-head gasket, clear P0301 and P0302, and verify the engine starts and runs without misfire or driveline chatter.

CUSTOMER CONCERN The A/C cools in electric operation but blows warm when the gasoline engine starts; DTC B1441 is stored and the air-mix door does not respond. CAUSE The air-mix actuator harness circuit board passed an input frequency signal but produced no corresponding output; the actuator was also replaced because an internal short may have damaged the circuit. CORRECTION Remove and replace the air-mix damper actuator and its control wiring harness, clear B1441, and verify