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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