Toyota 4Runner: Problem Symptoms Table

Toyota 4Runner Service Manual / Steering / Power Assist Systems / Power Steering System / Problem Symptoms Table

PROBLEM SYMPTOMS TABLE

HINT:

Use the table below to help determine the cause of problem symptoms. If multiple suspected areas are listed, the potential causes of the symptoms are listed in order of probability in the "Suspected Area" column of the table. Check each symptom by checking the suspected areas in the order they are listed. Replace parts as necessary.
Inspect the fuses and relays related to this system before inspecting the suspected areas below.

Power Steering System

Symptom	Suspected Area	See page
Hard steering	Tires (Improperly inflated)
	Power steering fluid level (Low)
	Drive belt (Loose)
	Front wheel alignment (Incorrect)
	Steering system joints (Worn)	-
	Suspension arm ball joints (Worn)
	Steering column (Binding)	-
	Vane pump assembly
	Rack and pinion power steering gear assembly
Poor return	Tires (Improperly inflated)
	Front wheel alignment (Incorrect)
	Steering column (Binding)	-
	Rack and pinion power steering gear assembly
Excessive play	Steering system joints (Worn)	-
	Suspension arm ball joints (Worn)
	Intermediate shaft, Sliding yoke (Worn)	-
	Front wheel bearing (Worn) (for 2WD)
	Front wheel bearing (Worn) (for 4WD)
	Rack and pinion power steering gear assembly
Abnormal noise	Power steering fluid level (Low)
	Steering system joints (Worn)	-
	Vane pump assembly
	Rack and pinion power steering gear assembly
Power steering system does not operate	IG power source circuit
	VFC power steering solenoid circuit
	Power steering ECU communication circuit
	Vehicle stability control system
	Steering angle sensor
	SFI system
	Power steering ECU assembly
When the vehicle is idling, steering effort is high (with the vehicle stopped)	Tire size and tire pressure
	Power steering fluid level and pressure
	Front wheel alignment
	IG power source circuit
	VFC power steering solenoid circuit
	Power steering ECU communication circuit
	Steering angle sensor
	Power steering ECU assembly
Even if vehicle speed increases, steering effort does not increase	VFC power steering solenoid circuit
	Power steering ECU communication circuit
	Vehicle stability control system
	Power steering ECU assembly
Power steering warning light is abnormal	Power steering warning light circuit

System Description

SYSTEM DESCRIPTION 1. DESCRIPTION (a) In the Variable Flow Control (VFC) power steering system, the power steering ECU assembly receives the steering angle signal, steering zero point memory, the ...

Terminals Of Ecu

TERMINALS OF ECU 1. CHECK POWER STEERING ECU ASSEMBLY (a) Measure the voltage and resistance according to the value(s) in the table below. Terminal No. (Symbol) Wiring Col ...

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Side Auto Step LH Stowing Timeout (51-56)
DESCRIPTION When fully deploying or stowing the automatic running board takes more than 4 seconds, or when the side auto step motor hall sensor pulse signal exceeds the maximum pulse count, the side auto step ECU halts the operation of the automatic runni ...

Inspection
INSPECTION PROCEDURE 1. INSPECT FRONT SHOCK ABSORBER ASSEMBLY LH (a) Compress and extend the shock absorber rod and check that there is no abnormal resistance or unusual sound during operation. If there is any abnormality, replace the front shock absorbe ...