Toyota Sienna Service Manual: Customer problem analysis

Toyota Sienna Service Manual / Introduction / How to troubleshoot ecu controlled systems / How to proceed with troubleshooting / Customer problem analysis

HINT:

In troubleshooting, confirm that the problem symptoms have been accurately identified. Preconceptions should be discarded in order to make an accurate judgment. To clearly understand what the problem symptoms are, it is extremely important to ask the customer about the problem and the conditions at the time the malfunction occurred.
Gather as much information as possible for reference.
Past problems that seem unrelated may also help in some cases.
The following 5 items are important points in the problem analysis:

What	Vehicle model, system name
When	Date, time, occurrence frequency
Where	Road conditions
Under what conditions?	Running conditions, driving conditions, weather conditions
How did it happen?	Problem symptoms

Operation flow

HINT: Perform troubleshooting in accordance with the procedures below. The following is an outline of basic troubleshooting procedures. Confirm the troubleshooting procedures for the circuit you a ...

Symptom confirmation and diagnostic trouble code

HINT: The diagnostic system in the SIENNA has various functions. The first function is the Diagnostic Trouble Code (DTC) check. A DTC is a code stored in the ECU memory whenever a malfunctio ...

Other materials:

On-vehicle inspection
1. INSPECT DRIVE BELT (a) Visually check the drive belt for excessive wear, frayed cords, etc. If any defect is found, replace the drive belt. HINT: Cracks on the rib side of a belt are considered acceptable. Replace the belt if there are any missing ribs. 2. CHECK POWER STEERING FLUID ...

Rear Airbag Sensor RH Circuit Malfunction
DTC B1154/38 Rear Airbag Sensor RH Circuit Malfunction DESCRIPTION The rear airbag sensor RH circuit consists of the center airbag sensor assembly and rear airbag sensor RH. If the center airbag sensor assembly receives signals from the rear airbag sensor RH, it judges whether or not the ...

If your vehicle overheats
The following may indicate that your vehicle is overheating. The needle of the engine coolant temperature gauge enters the red zone or a loss of engine power is experienced. (For example, the vehicle speed does not increase.) The warning message indicating overheats is shown on the mult ...