Toyota RAV4 Service Manual: Symptom simulation
The most difficult case in troubleshooting is when no problem symptoms occur. In such a case, a thorough problem analysis must be carried out. A simulation of the same or similar conditions and environment in which the problem occurred in the customer's vehicle should be carried out. No matter how much skill or experience a technician has, troubleshooting without confirming the problem symptoms will lead to important repairs being overlooked and mistakes or delays.
With a problem that only occurs when the engine is cold or as a result of vibration caused by the road during driving, the problem can never be determined if the symptoms are being checked on a stationary vehicle or on a vehicle with a warmedup engine. Vibration, heat or water penetration (moisture) is difficult to reproduce. The symptom simulation tests below are effective substitutes for the conditions and can be applied on a stationary vehicle.
Important points in the symptom simulation test: in the symptom simulation test, the problem symptoms as well as the problem area or parts must be confirmed. First, narrow down the possible problem circuits according to the symptoms. Then, connect the tester and carry out the symptom simulation test, judging whether the circuit being tested is defective or normal. Also, confirm the problem symptoms at the same time.
Refer to the problem symptoms table for each system to narrow down the possible causes.
- Vibration method:
When a malfunction seems to occur as a result of vibration.
- Part and sensor
Apply slight vibration with a finger to the part of the sensor suspected to be the cause of the problem, and check whether or not the malfunction occurs.
Applying strong vibration to relays may open them.
Slightly shake the connector vertically and horizontally.
- Wire harness
Slightly shake the wire harness vertically and horizontally.
The connector joint and fulcrum of the vibration are the major areas that should be checked thoroughly.
- Heat method:
When a malfunction seems to occur when the area in question is heated.
- Heat the component that is the possible cause of the malfunction with a hair dryer or similar device. Check if the malfunction occurs.
Do not heat to more than 60°c (140°f).
Exceeding this temperature may damage components.
- Do not apply heat directly to the parts in the ecu.
- Water sprinkling method:
When a malfunction seems to occur on a rainy day or in high-humidity.
- Sprinkle water onto the vehicle and check if the malfunction occurs.
- Never sprinkle water directly into the engine compartment. Indirectly change the temperature and humidity by spraying water onto the front of the radiator.
- Never apply water directly onto the electronic components.
If the vehicle has or had a water leakage problem, the leakage may have damaged the ecu or connections. Look for evidence of corrosion or short circuits. Proceed with caution during water tests.
- High electrical load method:
When a malfunction seems to occur when the electrical load is excessive.
- Turn on the heater blower, headlight, rear window defogger and all other electrical loads.
Check if the malfunction reoccurs.
Stop light switch circuit
Description While driving with the cruise control, if the ecm detects that the brake pedal is depressed, the cruise control operation will be canceled. The stop light switch sends brake pedal status signals to the ecm. When the brake pedal is not depressed, terminal st1- is equal to the ...
Cooling fan relay
On-vehicle inspection Disconnect cable from negative battery terminal Caution: Wait at least 90 seconds after disconnecting the cable from the negative (-) battery terminal to prevent airbag and seat belt pretensioner activation. Remove engine room no. 2 Relay block cover Inspect ...
Parking brake cable
Components Removal Remove rear console box sub-assembly Remove the rear console box (see page ip-16). Hint: Refer to the procedures from the removal of the no. 1 Console upper panel garnish up until the removal of the rear console box sub-assembly. Loosen lock nut and no.