Page 441 of 4770

Disconnect the EFI fuse (15 A) for 10 sec. or more, with IG switch OFF. Initiate
test mode (Connect terminals TE2 and E1 of data link connector, 1 or 2 with IG
switch OFF).
CIRCUIT DESCRIPTION (Cont'd)
DIAGNOSIS TROUBLE CODE DETECTION DRIVING PATTERN
Purpose of the driving pattern.
(a) To simulate diagnostic trouble code detecting condition after diagnostic trouble code is
recorded.
(b) To check that the malfunction is corrected when the repair is completed confirming that diag-
nostic trouble code is no longer detected.
Malfunction: Open in EGR gas temp. sensor circuit
Start the engine and warm up.
After the engine is warmed up, let it idle for 3 min.
With the A/C ON and transmission in 5th gear A/T in ªDº position), drive at
55 ± 60 mph (88 ± 96 km/h) for 4 min. or less.
HINT: If a malfunction exists, the malfunction indicator lamp will light up dur-
ing step (4) .
NOTICE: If the conditions in this test are not strictly observed, detection of
the malfunction will not be possible.
± 5S±FE ENGINECIRCUIT INSPECTIONEG1±391
Page 442 of 4770
Check for open and short in harness and
connector between EFI main relay and ECM.
Check for open in harness and connector
between EGR gas temp. sensor and ECM. Check voltage of VSV for EGR Power source.
Repair or replace harness or
connector.
Repair or replace harness or
connector. Check resistance of EGR gas temp. sensor. Check EGR system (See page EG1±153) .
WIRING DIAGRAM
DIAGNOSTIC CHART
Check resistance of VSV for EG R.
Replace EGR gas temp. sensor.
Check and replace ECM.Check and replace ECM.Replace VSV for EG R.
Repair EGR system.
± 5S±FE ENGINECIRCUIT INSPECTIONEG1±392
Page 443 of 4770
(1) Remove glove compartment.
(See page EG1±234).
(2) Warm up engine to normal operating temperature.
Check voltage between terminal EGR of engine control module
connector and body ground.
INSPECTION PROCEDURE
Go to step Measure voltage between terminal EGR of en-
gine control module connector and body ground.
Voltage: 9 ±14 V
± 5S±FE ENGINECIRCUIT INSPECTIONEG1±393
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Remove VSV for EGR. (See page EG1±154, 155*).
Measure resistance between terminals of VSV for
EG R.
Check for open and short in harness and connector between EFI
main relay and VSV for EGR, VSV and engine control module. (See page IN±31). Check resistance between terminals of VSV for EGR.
Check EGR system (See page EG1±153).
Check and replace engine control module.Repair or replace harness or connector. Replace VSV for EGR.
Repair EGR system. Resistance: 33 ± 39 (Cold)
*: Except California specification vehicle.
± 5S±FE ENGINECIRCUIT INSPECTIONEG1±394
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Remove EGR gas temp. sensor.
Measure resistance between terminals of EG R
gas temp. sensor connector.
Resistance: 64 ± 97 k
at 50C (122F)
11 ±16 k
at 100C (212F)
2 ± 4 k
at 150C (302F)
Check for open in harness and connector between EGR gas temp.
sensor and engine control module (See page IN±31). Check resistance of EGR gas temp, sensor.
Check and replace engine control module.Repair or replace harness or connector. Replace EGR gas temp. sensor.
± 5S±FE ENGINECIRCUIT INSPECTIONEG1±395
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CIRCUIT DESCRIPTION
Park/Neutral Position Switch Signal*
The ECM uses the signals from the park/neutral position switch to determine whether the transmis±
sion is in park or neutral, or in some other gear.
Air Conditioning Switch Signal
The ECM uses the output from the air conditioning switch to determine whether or not the air
conditioning is operating so that it can increase the idling speed of the engine if necessary.
Throttle Position Sensor IDL Signal
The IDL contacts are mounted in the throttle position sensor, and detects the idle condition.
(1) 3 sec. or more after engine starts with closed
throttle position switch OFF (IDL).
(2) * Park/ Neutral position switch OFF.
(Shift position in ªRº, ªDº, ª2º or ªLº positions).
(3) A/C switch ON.
*: Only vehicles with A/T.
HINT: In this circuit, diagnosis can only be made in the test mode.
wThrottle position sensor IDL circuit
wAccelerator pedal and cable
wPark/Neutral position switch circuit
wA/C switch circuit
wECM Diagnostic Trouble Code Detecting Condition
DIAGNOSTIC CHART
WIRING DIAGRAM
Trouble Area
DTC 51 Switch Condition Signal Circuit
DTC No.
± 5S±FE ENGINECIRCUIT INSPECTIONEG1±396
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Check and repair harness or connector between
sensor and ECM.Proceed to next circuit inspection shown on
matrix chart (See page EG1±327).
Check for open and short in harness and
connector between A/C amplifier and ECM.Adjust or replace throttle position sensor
(See page EG1±209). Check resistance of throttle position sensor.
Repair or replace harness or connector.
DIAGNOSTIC CHART
Check and replace A/C amplifier. Check input circuit of A/C.NG (PNP)
NG (A/C)
Check and replace ECM.Check for input signal.See page EG1±400.
NG (IDL)
± 5S±FE ENGINECIRCUIT INSPECTIONEG1±397
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Setting the test mode.
(1) Turn ignition switch OFF.
(2) Connect terminals TE2 and E1 of DLC2.
(3) Turn ignition switch ON.
(For checking terminal IDL, disconnect the
vacuum hose from the throttle body, then
apply vacuum to the throttle opener (See page
EG1±204).)
(For checking terminal A/C, start the engine.)
(4) Connect terminals TE1 and E1 of DLC2.
*: Before the STA signal is input (ST is not ON),
diagnostic trouble code 43 is also output. Check output condition of diagnostic trouble code 51.
Proceed to next circuit inspection shown on
matrix chart (See page EG1±327).IDL .... Go to step
A/C ... Go to step
INSPECTION PROCEDURE
PN P ... Go to page
EG1±400. Park/Neutral Position
Switch (PNP)
Accelerator pedal
depressed Accelerator pedal
released
Throttle Position
Sensor ( IDL)R, D, 2 or L position
A/C Switch (A/C)P or N position
A/C SW OFFA/C SW ONCondition
Normal*
Normal*
NormalCode
51*
51*
Check if code ª51º is output by the malfunc-
tion indicator lamp.
Diagnostic trouble code 42 is output with vehicle
speed 3 mph (5 km/h) or below.
± 5S±FE ENGINECIRCUIT INSPECTIONEG1±398