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:

Horn
To sound the horn, press on or close to the mark. WARNINGCaution while driving Do not adjust the steering wheel while driving. Doing so may cause the driver to mishandle the vehicle and cause an accident, resulting in death or serious injury. After adjusting the steeri ...

Unmatched Encryption Code
DTC B2794 Unmatched Encryption Code DESCRIPTION This DTC is output when a key with an incomplete key code is inserted into the ignition key cylinder. DTC No. DTC Detection Condition Trouble Area B2794 Key with incomplete key code inserted Key IN ...

Insufficient Coolant Temperature for Closed Loop Fuel Control
DTC P0125 Insufficient Coolant Temperature for Closed Loop Fuel Control DESCRIPTION Refer to DTC P0115 DTC No. DTC Detection Condition Trouble Area P0125 Engine coolant temperature (ECT) does not reach closed-loop enabling temperature for 20 minutes (t ...