The 2006 Toyota Camry occasionally stalls suddenly while driving.
2026-03-27
Background
Vehicle Model: 2006 Toyota Camry with 2.4L engine and automatic transmission
VIN: LVGBE40K26G××××××
Mileage: 194,587 km
Fault Phenomenon
The customer brought the vehicle to the shop and reported that the engine would suddenly stall intermittently while driving. The vehicle had been repaired at the workshop multiple times, yet the fault persisted.
Technicians took delivery for inspection. The fault recurred after several road tests, with the engine cutting out automatically. The MIL (Malfunction Indicator Lamp) and VSC warning light on the instrument cluster illuminated, while the AFS OFF indicator flashed. The dashboard displayed the prompt "Check VSC".
A diagnostic scanner failed to establish automatic communication with the vehicle. Manual connection yielded the error message "Communication error with engine ECU". No relevant DTCs (Diagnostic Trouble Codes) were retrieved upon accessing control modules.
Fault Analysis
Based on the symptoms, potential root causes are listed as follows:
- Open circuit in ECM power supply circuit
- Open circuit in ECM ground circuit
- Open or short circuit on ECM CAN communication lines
- Internal failure of the ECM
- Other associated malfunctions
Repair Procedure
Connect the diagnostic scanner to test the CAN system and scan all control modules; the ECM was not detected.
Circuit inspection was carried out per the wiring diagram: 12V was measured at pin 20 of the engine ECM A24 connector.
With the ignition switch turned ON, pins 1 and 2 of the A24 connector showed 0V, indicating an open circuit on the EFI 2 power control circuit. A test light was used to inspect the EFI 2 fuse; power was present on both sides of the fuse, ruling out a blown fuse.
It was suspected that an open circuit existed between the output terminal of the fuse holder and the A24 connector. Multimeter measurement of resistance between the EFI 2 fuse and pin 2 of the A24 connector returned a reading of 0.5Ω, confirming no open circuit. The engine restarted and ran smoothly afterward, and the vehicle returned to normal operation.
Fault Conclusion
The series of tests confirmed the vehicle’s issue stemmed from poor contact in wiring or connectors. The faulty contact area was located between the EFI 2 fuse and the A24 connector, covering two connection points: the EFI 2 fuse holder and the A24 connector.
Visual inspection of the A24 connector pins revealed no deformation, corrosion or insufficient terminal clamping force.
Examination of the EFI 2 fuse holder uncovered an extra copper wire wrapped around the fuse terminal (See Figure 3), alongside melted and carbonized damage on the fuse holder housing (See Figure 4).
Figure 3. leftover copper wire
Figure 4: Relocation of the fuse holder
After reinstalling the fuse, the engine would still stall automatically intermittently. An infinite resistance reading was measured between the fuse holder terminals and the fuse.
Improper wiring modification was carried out previously. One wire was left in place when auxiliary wiring was disconnected, resulting in intermittent poor contact between the EFI 2 fuse pins and the holder. This caused melting damage to the fuse holder and intermittent engine stall.
The original fuse holder was damaged and no replacement unit was in stock. The fuse pins were transferred to an empty spare fuse holder instead. After reassembly and road testing, the fault was resolved.
Remarks
Fault Summary
This case serves as a reminder to follow standardized operating procedures during routine maintenance to avoid human-induced faults. Customers should also be informed of the potential hazards of aftermarket accessory wiring modifications, which may compromise driving safety.
