TOYOTA CAMRY 1999 Service Repair Manual

± DIAGNOSTICSCRUISE CONTROL SYSTEM
DI±339
DTC 23 Vehicle Speed Signal Abnormal
CIRCUIT DESCRIPTION
See page DI±336.
DTC No.DTC Detecting ConditionTrouble Area
23Vehicle speed sensor pulse is abnormal.
Vehicle speed sensor

Cruise control ECU
WIRING DIAGRAM
See page DI±336.
INSPECTION PROCEDURE
1 Check vehicle speed sensor (See Pub. No. RM654U on page BE±47).
NG Replace vehicle speed sensor.
OK
Check and replace cruise control ECU
(See page IN±29).
DI08Q±11

I00283
Cruise Control ECU
CMS
CCS
GND
CMS
W±L
W±B
W Cruise Control Switch

Main Switch

Control Switch
1J
78
W±B5
4
3
W±B MAIN
CANCEL
SET/COAST
RES/ACC
A11
10
16 CCS
EP
J6
J6J7 AJ/C
A
A
1J
W±B J/C
IFC16
C16
C16
J9
Instrument Panel J/B DI±340
± DIAGNOSTICSCRUISE CONTROL SYSTEM
DTC 32 Control Switch Circuit (Cruise Control
Switch)
CIRCUIT DESCRIPTION
This circuit carries the SET/COAST, RESUME/ACCEL and CANCEL signals (each voltage) to the ECU.
DTC No.DTC Detecting ConditionTrouble Area
32Short in control switch circuit.
Cruise control switch
Harness or connector between cruise control ECU and
cruise control switch, cruise control switch and body ground
Cruise control ECU
WIRING DIAGRAM
DI08R±13

Input SignalIndicator Light
Blinking Pattern
SET/COAST
switch
RESUME/ACCEL
switch
CANCEL switch2 Pulses
ON
OFF
ON
OFF3 Pulses
ON
OFFSW OFF
SW ON
AB0119
I00168
I00171
ON
CCS
(±) (+)
± DIAGNOSTICSCRUISE CONTROL SYSTEM
DI±341
INSPECTION PROCEDURE
1 Input signal check.
PREPARATION:
See input signal check on page DI±319.
CHECK:
Check the indicator light operation when each of the SET/
COAST, RESUME/ACCEL and CANCEL is turned on.
OK:
SET/COAST, RESUME/ACCEL switch
The signals shown in the table on the left should be
output when each switch is ON. The signal should
disappear when the switch is turned OFF.
CANCEL switch
The indicator light goes off when the cancel switch is
turned ON.
OK Wait and see.
NG
2 Check voltage between terminals CCS of cruise control ECU connector and body
ground.
PREPARATION:
(a) Remove the ECU with connector still connected.
(b) Turn ignition switch ON.
CHECK:
Measure voltage between terminals 18 of ECU connector and
body ground, when each of the SET/COAST, RESUME/AC-
CEL and CANCEL is turned ON.
Switch positionResistance (V)
Neutral10 ± 16 V
RES/ACC0.8 ± 3.7 V
SET/COAST2.5 ± 6.3 V
CANCEL4.2 ± 8.8 V
NG Proceed to next circuit inspection shown on
problem symptoms table (See page DI±328).
OK

N16045
3 4
DI±342
± DIAGNOSTICSCRUISE CONTROL SYSTEM
3 Check control switch.
PREPARATION:
(a) Remove steering wheel center pad.
(b) Disconnect the control switch connector.
CHECK:
Measure resistance between terminals 3 and 4 of control switch
connector when control switch is operated.
Switch positionResistance (W)
Neutral8 (No continuity)
RES/ACC50 ± 80
SET/COAST180 ± 220
CANCEL400 ± 440
NG Replace control switch.
OK
4Check harness and connector between cruise control ECU and cruise control switch,
cruise control switch and body ground (See page
IN±29).
NG Repair or replace harness or connector.
OK
5 Input signal check (See step 1).
OK Wait and see.
NG
Check and replace cruise control ECU
(See page IN±29).

N21220
Cruise Control ECU
IDL 13
L±R ECM
IDLOE43
C16
± DIAGNOSTICSCRUISE CONTROL SYSTEM
DI±343
DTC 51 Idle Signal Circuit
CIRCUIT DESCRIPTION
When the idle switch is turned ON, a signal is sent to the ECU. The ECU uses this signal to correct the dis-
crepancy between the throttle valve position and the actuator position sensor value to enable accurate
cruise control at the set speed. If the idle switch is malfunctioning, problem symptoms also occur in the en-
gine, so also inspect the engine.
DTC No.DTC Detecting ConditionTrouble Area
51Short in idle signal circuit.

Harness or connector between ECM and throttle position
sensor

Throttle position sensor

Harness or connector between cruise control ECU and ECM

Cruise control ECU
WIRING DIAGRAM
DI08S±11

AB0119
I00167
I00172
ON
IDL
(±) (+)
DI±344
± DIAGNOSTICSCRUISE CONTROL SYSTEM
INSPECTION PROCEDURE
1 Check voltage between terminal IDL of cruise control ECU connector and body
ground.
PREPARATION:
(a) Remove the ECU with connector still connected.
(b) Disconnect the ECM connector.
(c) Turn ignition switch ON.
CHECK:
Measure voltage between terminal IDL of ECU connector and
body ground when the throttle valve is fully closed and fully
opened.
OK:
Throttle valve positionVoltage
Fully opened10 ± 14 V
Fully closedBelow 2 V
OK Proceed to next circuit inspection shown on
problem symptoms table (See page DI±328).
NG
2 Check harness and connector between ECM and throttle position sensor (See
page IN±29).
NG Repair or replace harness or connector.
OK
3 Check throttle position sensor circuit (See page DI±39).
NG Replace throttle position sensor.
OK

I00052
Throttle Position Sensor
3
4
± DIAGNOSTICSCRUISE CONTROL SYSTEM
DI±345
4 Check throttle position sensor.
PREPARATION:
Disconnect the throttle position sensor connector.
CHECK:
Measure resistance between terminals 3 and 4 of throttle posi-
tion sensor connector when the throttle valve is fully closed and
fully opened.
OK:
Throttle valve positionResistance
Fully opened1 MW or higher
Fully closedBelow 2.3 kW
NG Replace throttle position sensor.
OK
5 Check for open and short in harness and connector between cruise control ECU
and ECM (See page IN±29).
NG Repair or replace harness or connector.
OK
Check and replace cruise control ECU (See
page IN±29).

I08461
A
J6A
J6 J/C
J/CJ9
A
W±BW±B
Instrument Panel J/B
7
1J
1J8
IF Battery FL MAIN B±G1
F9FL BLOCK
ALT
F141B±R 7
1C4
1B Instrument Panel J/B
STOP W2
3Stop Light Switch
1
4G±W1R4 Instrument Panel J/B
5
1R
R±Y
G±B
W±BCruise Control
Actuator
3
4G±WAA J23
J/C
G±W2
C16
C16
8Cruise Control ECU
STP±
L
DI±346
± DIAGNOSTICSCRUISE CONTROL SYSTEM
Stop Light Switch Circuit
CIRCUIT DESCRIPTION
When the brake pedal is depressed, the stop light switch sends a signal to the ECU. When the ECU receives
this signal, it cancels the cruise control.
A fail±safe function is provided so that the cancel functions normally, even if there is a malfunction in the stop
light signal circuit.
The cancel conditions are: Battery positive voltage at terminal STP±
When the brake is ON, battery positive voltage normally is applied through the STOP fuse and stop light
switch to terminal STP± of the ECU, and the ECU turns the cruise control OFF.
If the harness connected to terminal STP± has an open circuit, terminal STP± will have battery positive volt-
age and the cruise control will be turned OFF.
Also, when the brake is ON, the magnetic clutch circuit is cut mechanically by the stop light switch, turning
the cruise control OFF. (See page DI±331 for operation of the magnetic clutch)
WIRING DIAGRAM
DI08T±12

Input SignalIndicator Light
Blinking Pattern
Stop Light
switch ON
LightOFF
ONSW OFF
SW ON
± DIAGNOSTICSCRUISE CONTROL SYSTEM
DI±347
INSPECTION PROCEDURE
1 Check operation of stop light.
CHECK:
Check that stop light comes ON when brake pedal is depressed, and turns OFF when brake pedal is re-
leased.
NG Check stop light system (See page BE±1).
OK
2 Input signal check.
CHECK:
(a) See input signal check on DI±319.
(b) Check the indicator light when the brake pedal is de-
pressed.
OK:
The indicator light goes OFF when the brake pedal is
depressed.
OK Proceed to next circuit inspection shown on
problem symptoms table (See page DI±328).
NG

AB0119
I00142
I00173
ON
STP±
(±) (+)
DI±348
± DIAGNOSTICSCRUISE CONTROL SYSTEM
3 Check voltage between terminal STP± of cruise control ECU connector and
body ground.
PREPARATION:
(a) Remove the ECU with connectors still connected.
(b) Turn ignition switch ON.
CHECK:
Measure voltage between terminal STP± of cruise control ECU
connector and body ground, when the brake pedal is de-
pressed and released.
OK:
Depressed10 ± 14 V
ReleasedBelow 1 V
OK Proceed to next circuit inspection shown on
problem symptoms table (See page DI±328).
NG
4 Check for open in harness and connectors between terminal STP± of cruise con-
trol ECU and stop light switch (See page IN±29).
NG Repair or replace harness or connector.
OK
Check and replace cruise control ECU
(See page IN±29).