relay TOYOTA SUPRA 1986 Service User Guide

INSPECTION PROCEDURE
(See page IN±30).
(See page EG±514).
Disconnect IAC valve connector.
Measure resistance between terminals shown be-
low.
Check IAC valve.
Check for open and short in harness and connector between EFI main relay
and IAC valve, IAC valve and engine control module (See page IN±30).
Repair or replace harness or connector.
Remove IAC Valve.
(1) Connect the battery positive lead to terminals
5 (B1) and 2 (B2), and the negative lead to ter±
minals 4(S1)Ð1(S2)Ð6(S3)Ð3(S4) in that or
der.
(2) Connect the battery positive lead to terminals
5 (B1) and 2 (B2) and the negative lead to ter±
minals 3(S4)Ð6(S3)Ð1(S2)Ð4(S1) in that or
der.
(1) The valve moves in the closing direction
(2) The valve moves in the opening direction.
Replace IAC valve.
Proceed to next circuit inspection shown on ma-
trix chart (See page EG±514).
TerminalResistance
EG±588± ENGINE2JZ±GTE ENGINE TROUBLESHOOTING

(See page IN±30).
(1) Connect SST (check harness ªAº).
(See page EG±510)
SST 09990±01000
(2) Turn ignition switch ON.
Measure voltage between terminal FPU of engine
control module connector and body ground.
Voltage: 9 Ð 14 V
Check voltage between terminal FPU of engine control module
connector and body ground.
Proceed to next circuit inspection shown
on matrix chart (See page Eg±514).
Repair or replace harness or connector.
Check for open and short in harness and connector between engine control
module and VSV, VSV and EFI main relay (See page IN±30).
Check and replace engine control module.
± ENGINE2JZ±GTE ENGINE TROUBLESHOOTINGEG±597

 
 
 Trouble Area
 
 
 
Malfunction
Indicator
Lamp*
1
 
 
 Memory*2
 
 
 See page
 
 
Trouble Area
 
 
Normal
Mode 
 
Test
Mode 
 
Memory
 
 
See page
 
 
 
 

Open or short in volume air flow meter circuit

Volume air flow meter

ECM
 
 
 
 
ON
 
 
 
 
N.A.
 
 
 
 

 
 
 
 
EG±438
 
 
 

ECM
 
 
 
ON
 
 
 
ON
 
 
 

 
 
 
EG±441
 
 
 
 

Open or short in throttle position sensor circuit

Throttle position sensor

ECM
 
 
 
 
ON
 
 
 
 
ON
 
 
 
 

 
 
 
 
EG±442
 
 
 
 
 
 
 
 
 

No.1 vehicle speed sensor

Telltale light RH

Open or short in No.1 vehicle speed sensor circuit

ECM
 
 
 
 
 
 
 
 
 
OFF
 
 
 
 
 
 
 
 
 
OFF
 
 
 
 
 
 
 
 
 

 
 
 
 
 
 
 
 
 
EG±445
 
 
 

Open or short in starter signal circuit

Open or short in ignition switch or starter relay circuit

ECM
 
 
 N.A.
 
 
 OFF
 
 
 X
 
 
 EG±448
 
 
 
 
 

Open or short in No.1 knock sensor circuit

No.1 knock sensor (looseness)

ECM
 
 
 
 
 
ON
 
 
 
 
 
N.A.
 
 
 
 
 

 
 
 
 
 
EG±450
 
 
 
 

ECM
 
 
 
 
ON
 
 
 
 
N.A.
 
 
 
 
X
 
 
 
 
EG±450
 
 
 
 
 

Open or short in No.2 knock sensor circuit

No.2 knock sensor (looseness)

ECM
 
 
 
 
 
ON
 
 
 
 
 
N.A.
 
 
 
 
 

 
 
 
 
 
EG±450
*1, 2: See page EG±396.
± ENGINE2JZ±GE ENGINE TROUBLESHOOTINGEG±395

MATRIX CHART OF PROBLEM SYMPTOMS
When the malfunction code is not confirmed in the diagnostic trouble code check and the problem still can not
be confirmed in the basic inspection, proceed to this matrix chart and troubleshoot according to the numbered
order given below.
EG±438EG±438EG±453EG±460EG±463EG±465EG±470EG±472EG±475EG±457EG±481AC±62ST±3, 12IG±4IG±5IG±7IG±7EG±9AT2±81BE±123IN±35
See page
Suspect area
Symptom
Engine does not crank
No initial combustion
No complete combustion
Engine cranks normally
Cold engine
Hot engine
Incorrect first idle
High engine idle speed
Low engine idle speed
Rough idling
Hunting
Hesitation/Poor acceleration
Muffler explosion (after fire)
Surging
Soon after starting
After accelerator pedal depressed
After accelerator pedal released
During A/C operation
When shifting N to D
Does notstart
Difficult tostart
Poor Idling
Poor
Driveability
Engine Stall
Volume air flow meter circuitECM power source circuitPark/neutral position switch circuitSwitch condition signal circuitEGR systemStarter signal circuitStarter and Starter relayA/C signal circuit (Compressor circuit)VSV circuit for fuel pressure controlFuel pump control circuitIAC valve circuitInjector circuitBack up power source circuitIgnition coilSpark plugIgnition signal circuit (Spark test)CompressionA/T faultyDistributorEngine control module (ECM)Theft deterrent ECU
EG±408± ENGINE2JZ±GE ENGINE TROUBLESHOOTING

INSPECTION PROCEDURE (Only for California specification vehicles)
HINT: If diagnostic trouble code º21º is output, check the main heated oxygen sensor (Fr) circuit.
If diagnostic trouble code º28º is output, check the main heated oxygen sensor (Rr) circuit.
Check voltage between terminals HT1, HT2 of engine control module
connector and body ground.
Connect SST (check harness ªAº).
See page EG±404)
SST 09990±01000
Measure voltage between terminals HT1, HT2 of engine
control module connector and body ground.
Voltage: 9 Ð 14 V
Go to step
Check main heated oxygen sensor heater.
Disconnect main heated oxygen sensor connector.
Measure resistance between terminals 1 and 2 of main
heated oxygen sensor connector.
Resistance: 11 Ð 16
at 20°C (68°F)
Replace main heated oxygen sensor.
Check and repair harness or connector between main
relay and main heated oxygen sensor, main heated oxy-
gen sensor and engine control module.
EG±422± ENGINE2JZ±GE ENGINE TROUBLESHOOTING

Check sub heated oxygen sensor heater.
Disconnect sub heated oxygen sensor connector.
(See page EG±250)
Measure resistance between terminals 1 and 2 of
sub heated oxygen sensor connector.
Resistance: 11 Ð 16
at 20°C (68°F)
Check for open and short in harness and connector between EFI main relay and
engine control module (See page
IN±30).
Replace sub heated oxygen sensor.
Repair or replace harness or connector.
Check and replace engine control module.
Check voltage between terminal HT3 of engine control module connector and
body ground.
Warm up engine to normal operating temperature.
Measure voltage between terminal HT3 of engine
control module connector and body ground, when
engine is idling and racing at 3,500 rpm.
Replace sub heated oxygen sensor.
Check and replace engine control module.
*: It is probable the oxygen sensor has
deteriorated.
Usually, this cannot be confirmed by visual
inspection.
± ENGINE2JZ±GE ENGINE TROUBLESHOOTINGEG±437

DTC 43 Starter Signal Circuit
CIRCUIT DESCRIPTION
When the engine is being cranked, the intake air flow is slow, so fuel vaporization is poor. A rich mixture is there-
fore necessary in order to achieve good startability. While the engine is being cranked, the battery positive volt-
age is applied to terminal STA of the ECM. The starter signal is mainly used to increase the fuel injection volume
for the starting injection control and after±start injection control.
 DTC No. Diagnostic Trouble Code Detecting Condition Trouble Area
 
 
43
 
  No starter signal to ECM
 
 
Open or short in starter signal circuit


Open or short in ignition switch or starter
 
 
43 
 
No starter signal to ECM
 
 
Oen or short in ignition switch or starter
relay circuit


ECM
EG±448± ENGINE2JZ±GE ENGINE TROUBLESHOOTING

INSPECTION PROCEDURE
HINT: This diagnostic chart is based on the premise that the engine is being cranked under normal conditions.
If the engine does not crank, proceed to the matrix chart of problem symptoms on page EG±408.
Check output condition of diagnostic trouble code 43.
Check and replace engine control module.
Setting the test mode.
(1) Turn ignition switch OFF.
(2) Connect terminals TE2 and E1 of DLC2.
(3) Turn ignition switch ON.
(Don't start the engine)
(4) Connect terminals TE1 and E1 of DLC2.
Check if code ª43º is output by the malfunction
indicator lamp.
Code ª43º is output.
Start the engine.
Check if code ª43º disappears.
Code ª43º is not output.
Proceed to next circuit inspection shown on ma-
trix chart (See page
EG±408).
Check for open in harness and connector between engine control module
and starter relay (See page
IN±30).
Repair or replace harness or connector.
Check and replace engine control module.
± ENGINE2JZ±GE ENGINE TROUBLESHOOTINGEG±449

INSPECTION PROCEDURE
(See page
EG±404)
(See page
EG±240)
Check voltage between terminal EGR of engine control module connector
and body ground.
(1) Connect SST (check harness ªAº).
(See page EG±404)
SST 09990±0100
(2) Warm up engine to normal operating
temperature.
Measure voltage between terminal EGR of engine
control module connector and body ground.
Voltage: 9 Ð 14 V
Repair or replace harness of connector.
Check resistance between terminals of VSV for EGR.
Remove VSV for EGR. (See page EG±240)
Measure resistance between terminals of VSV for
EGR.
Resistance: 38.5 Ð 44.5
at 20°C (68°F)
Check and replace engine control module.
Check for open and short in harness and connector between EFI main relay
and VSV for EGR, VSV for EGR and engine control module. (See page
IN±30)
Replace VSV for EGR.
± ENGINE2JZ±GE ENGINE TROUBLESHOOTINGEG±455

(1) Turn ignition switch ON.
(2) Using SST, connect terminals +B and FP of
data link connector1.
SST 09843±18020
Check that there is pressure in the hose from the
fuel filter.
Fuel pressure can be felt.
Repair or replace harness or connector.Repair or replace harness or connector.
Check fuel pump operation.
Check for open and short in harness and connector between terminals +B
e +B, FP e FP of the data link connector 1 and fuel pump ECU (See page
IN±30).
Check voltage of terminal +B of data link connector 1.
Turn ignition switch ON.
Measure voltage between terminal +B of data link
connector 1 and body ground.
Fuel pressure can be felt.
Check for ECM power source circuit (See page
EG±465), and check for open in harness and con-
nector between terminal +B of data link connec-
tor 1 and main relay.
INSPECTION PROCEDURE
EG±458± ENGINE2JZ±GE ENGINE TROUBLESHOOTING