Page 822 of 1500

AUTO A/C DIAGNOSIS
HEATER, AIR CONDITIONING AND VENTILATION55-121
STEP 17. Check the defogger.
(1) Let the engine run at 2,000 r/min, and check the printed
heater with the battery fully charged.
(2) Turn on the defogger switch, and use a voltmeter to
measure the voltage in each printed heater at middle point
A on the rear window glass.
The value should be approximately 6 volts.
Q: Does the defogger work normally?
YES : Replace the A/C-ECU. Check that the defogger
system works normally.
NO : Repair the defogger. Or replace rear glass. Refer to
GROUP 42, Rear Window Glass.P.42-12
INSPECTION PROCEDURE 9: Defogger Timer Function does not Operate.
.
CIRCUIT OPERATION
Turn ON the defogger switch. If the defogger does
not shut off after about 16 minutes then the defogger
timer is malfunctioning.
.
TROUBLESHOOTING HINT
Malfunction of the A/C-ECU
Malfunction of the defogger timer
Refer to component locations GROUP-70
Refer to configuration diagrams GROUP-80
Refer to circuit diagrams GROUP-90
DIAGNOSIS
Replace the A/C-ECU.
Page 823 of 1500
AUTO A/C DIAGNOSIS
HEATER, AIR CONDITIONING AND VENTILATION55-122
INSPECTION PROCEDURE 10: Malfunction of the A/C-ECU Power Supply System.
.
TECHNICAL DESCRIPTION (COMMENT)
The A/C-ECU power system may be defective if the
air conditioner, defogger, and outside/inside air
selection damper motor all do not operate normally.
.
TROUBLESHOOTING HINTS
Malfunction of the A/C-ECU
Damaged harness wires or connectors
Refer to component locations GROUP-70
Refer to configuration diagrams GROUP-80
Refer to circuit diagrams GROUP-90
DIAGNOSIS
Required Special Tool:
MB991223: Test Harness Set
STEP 1. Check A/C-ECU connector C-16 for loose,
corroded or damaged terminals, or terminals pushed back
in the connector.
Q: Is A/C-ECU connector C-16 in good condition?
YES : Go to Step 2.
NO : Repair or replace the connector. Refer to GROUP
00E, Harness Connector Inspection P.00E-2. Check
that the air conditioning works normally.
Page 829 of 1500

AUTO A/C DIAGNOSIS
HEATER, AIR CONDITIONING AND VENTILATION55-128
STEP 9. Check the wiring harness between A/C-ECU
connector C-16 (terminal 27) and the ground.
Q: Is the wiring harness between A/C-ECU connector C-16
(terminal 27) and ground in good condition?
YES : It can be assumed that this malfunction is intermittent.
Refer to GROUP 00, How to Use
Troubleshooting/Inspection Service Points
How to
Cope with Intermittent Malfunctions P.00-14. check
that the air conditioning works normally.
NO : Repair the wiring harness. Check that the air
conditioning works normally.
INSPECTION PROCEDURE 12: When Sunlight Intensity Changes, Air Outlet Temperature Does Not
Change.
.
CIRCUIT OPERATION
When the blower air temperature cannot be changed
even if the preset temperature is changed, the sen-
sors may be defective.
.
TROUBLESHOOTING HINTS
Improper amount of refrigerant
Malfunction of the A/C pressure sensor
Malfunction of the photo sensor
Malfunction of the A/C-ECU
The wiring harness or connectors may have
loose, corroded, or damaged terminals, or termi-
nals pushed back in the connector.
Refer to component locations GROUP-70
Refer to configuration diagrams GROUP-80
Refer to circuit diagrams GROUP-90
Page 1335 of 1500
ENGINE CONTROL
ENGINE AND EMISSION CONTROL17-4
SYMPTOM CHARTM1171002200292
SYMPTOM PROCEDURES
INSPECTION PROCEDURE 1: Throttle Valve Will Not Fully Open or Close
.
COMMENT
The throttle body or accelerator pedal position (APP)
sensor is suspected.
.
TROUBLESHOOTING HINTS (THE MOST
LIKELY CAUSES FOR THIS CASE:)
Malfunction of the throttle body.
Malfunction of the accelerator pedal position
(APP) sensor.
Malfunction of the Engine ECU.
Circuit drawings
Refer to circuit diagrams GROUP-90
Refer to configuration diagrams GROUP-80
Refer to component locations GROUP-70 SYMPTOM INSPECTION PROCEDURE REFERENCE PAGE
Throttle Valve Will Not Fully Open or Close 1
P.17-4
Accelerator Pedal Operation Not Smooth (Over
Acceleration)2
P.17-6
Page 1337 of 1500
ENGINE CONTROL
ENGINE AND EMISSION CONTROL17-6
INSPECTION PROCEDURE 2: Accelerator Pedal Operation Not Smooth (Over Acceleration)
.
COMMENT
The accelerator pedal, its installation condition or the
accelerator pedal position (APP) sensor is sus-
pected.
.
TROUBLESHOOTING HINTS (THE MOST
LIKELY CAUSES FOR THIS CASE:)
Malfunction of the accelerator pedal.
Incorrectly installed accelerator pedal.
Malfunction of the accelerator pedal position
(APP) sensor.
Circuit drawings
Refer to circuit diagrams GROUP-90
Refer to configuration diagrams GROUP-80
Refer to component locations GROUP-70
DIAGNOSIS
Required Special Tools:
MB991958: Diagnostic Tool (MUT-III Sub Assembly)
MB991824: V.C.I.
MB991827: MUT-III USB Cable
MB991910: MUT-III Main Harness A
STEP 1. Check if the accelerator pedal is installed
correctly.
Q: Is the accelerator pedal installed correctly?
YES : Go to Step 2.
NO : Replace and reinstall the accelerator pedal. (Refer to
P.17-9). Go to Step 3.
Page 1346 of 1500

AUTO-CRUISE CONTROL
ENGINE AND EMISSION CONTROL17-15
DIAGNOSTIC TROUBLE CODE PROCEDURES
DTC P0830: Clutch Switch (5M/T Only)
.
CIRCUIT OPERATION
A 5 Volt power supply is applied to the clutch
switch output terminal (terminal No. 1) from the
ENGINE-ECU(terminal No. B-21 pin 41) when
the clutch pedal is applied the power supply is
switched to earth.
.
TECHNICAL DESCRIPTION
The ENGINE-ECU uses the clutch switch earth-
ing as a signal that clutch pedal has been
applied.
.
DTC SET CONDITIONS
Check Conditions
Vehicle speed is above 50 km/h.Judgement Criteria
Gear shift is above 5 times.
Clutch control is below 2 times.
No MIL.
No Limp home.
.
TROUBLESHOOTING HINTS (The most
likely causes for this code to be set are:)
Clutch switch failed
Harness damage in clutch switch circuit, or con-
nector damage.
Refer to component locations GROUP-70
Refer to configuration diagrams GROUP-80
Refer to circuit diagrams GROUP-90
DIAGNOSIS
Required Special Tools:
: Diagnostic tool (MUT-III Sub Assembly)
MB991824: V.C.I.
MB991827: USB Cable
MB991910: Main Harness A
Page 1352 of 1500

AUTO-CRUISE CONTROL
ENGINE AND EMISSION CONTROL17-21
CIRCUIT OPERATION
This circuit judges the signals of each switch
("COAST/SET", "ACC/RES" and "CANCEL") of the
auto-cruise control switch. The Engine ECU detects
the state of the auto-cruise control switch by sensing
the voltages shown below.
When all switches are OFF: 4.7 5.0 volts
When the "CRUISE" (MAIN) switch is "ON": 0
0.3 volt
When the "COAST/SET" switch is ON: 2.0 2.8
volts
When the "ACC/RES" switch is ON: 3.3 4.1
volts
When the "CANCEL" switch is ON: 0.8 1.5 volts
.
DTC SET CONDITIONS
Check Condition
The "CRUISE" indicator lamp illuminates.Judgement Criteria
If the auto-cruise control switch is operated, this
DTC will be set when the Engine ECU terminal
voltage is different from the standard value.
.
TROUBLESHOOTING HINTS (THE MOST
LIKELY CAUSES FOR THIS CASE:)
Malfunction of the auto-cruise control switch.
Malfunction of the clock spring.
Damaged harness or connector.
Malfunction of the Engine ECU.
Circuit drawings
Refer to circuit diagrams GROUP-90
Refer to configuration diagrams GROUP-80
Refer to component locations GROUP-70
DIAGNOSIS
Required Special Tools:
MB991958: Diagnostic Tool (MUT-III Sub Assembly)
MB991824: V.C.I.
MB991827: MUT-III USB Cable
MB991910: MUT-III Main Harness A
MB991223: Harness Set
MB992044: ENGINE-ECU Check Harness
Page 1365 of 1500
AUTO-CRUISE CONTROL
ENGINE AND EMISSION CONTROL17-34
DTC 1575: Cancel Latch Signal System
.
DTC SET CONDITIONS
The Engine ECU communicates cancellation reten-
tion information between the two microprocessors.
This DTC is set when cancellation retention informa-
tion contains inconsistency.
.
TROUBLESHOOTING HINTS (THE MOST
LIKELY CAUSES FOR THIS CODE TO BE
SET ARE:)
Malfunction of the Engine ECU.
Circuit drawings
Refer to circuit diagrams GROUP-90
Refer to configuration diagrams GROUP-80
Refer to component locations GROUP-70
DIAGNOSIS
Replace the Engine ECU.[Refer to GROUP 13A, Engine ECU
13A-675] . Then check that diagnostic trouble code P1575 is
not set.