2007 Camry Engine No-Start
2026-06-15
Background
Vehicle Model: 2007 Toyota Camry
Mileage: 140,980 km
Fault Phenomenon
The customer reported the vehicle failed to start after maintenance and car washing at the shop.
Technician inspection: The security indicator light turns off when the key is inserted, and all instrument readings are normal. The battery has sufficient power. The starter motor cranks powerfully when attempting to start the engine; occasional backfire occurs but stalls immediately afterward.
Connect the vehicle’s DLC3 with IT2 to retrieve all fault codes, with no current or history DTCs detected.
Remove the spark plugs for a spark test, and no ignition spark is observed.
Turn off the ignition switch and restart the engine; backfire occurs with momentary ignition spark, which then disappears.
Use the active test function on IT2 to verify the fuel pump operates normally.
With the ignition switch ON, access the data list of the Immobiliser system via IT2. The immobiliser status shows "Set", which differs from the normal "Unset" state of undamaged vehicles with ignition ON.
Fault Analysis
Potential root causes are listed below:
- CAN communication malfunction
- Faulty engine ECU
- Key transmitter malfunction
- Defective key
- Malfunction of transponder key ECU assembly and associated circuits
- Other unknown causes
Measure the resistance between CANH (pin 6) and CANL (pin 14) of DLC3 with a multimeter; the reading is 60.8 Ω, within the standard normal range.
Repair Procedure
First, short-circuit terminals TC and CG of DLC3 for 30 minutes, yet the engine still cannot start.
Replace the original engine ECU with a matching functional unit from an identical vehicle and perform matching programming, but the fault remains unresolved.
Access the Immobiliser data list via IT2; the Antenna coil status displays "NORMAL", indicating the transponder key amplifier coil is intact.
After communicating with the customer, the customer brought a spare key from home, but the starting fault persists when using this spare key.
Suspicion then falls on the transponder key ECU assembly.
Dismantle the dashboard and internal frame to extract the transponder key ECU assembly. Upon disconnecting the connector, both the plug and receptacle show varying degrees of corrosion.
Pin E15-13 suffers the most severe corrosion (See Figure 2). According to the wiring diagram, pin E15-13 connects to the engine ECU.
Shop service records show no window film installation was performed in our workshop, while the front windshield is already fitted with tint film.
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Transponder Key ECU Assembly Connector
The fault was caused by water intrusion from window tinting.
