I26143
IDL
13
15
ECM
C17
Cruise Control ECU
VC
25
VTA
Y
E8
2
3
*1: Except 5VZ–FE
T1
Throttle Position Sensor
LG–R
17
5
E5 E6
2
9
E7
E8 E7
G–Y
*2: 5VZ–FE
*2
*1
*2
*1
*2
*1
IDLO
DI–742
–
DIAGNOSTICS
CRUISE CONTROL SYSTEM (w/o ETCS–i)
1004
Author:
Date:
2003 TOYOTA TACOMA (RM1002U)
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 a discrep-
ancy between the throttle valve position and the actuator position sensor values, and it enables accurate
cruise control at the set speed. If the idle switch malfunctions, problem symptoms occur also in the engine,
so inspect the engine then.
DTC No.
DTC Detection Condition
Trouble Area
51
Short 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
DI8ZJ–04
I21989
ON
(–)
(+)
IDL
–
DIAGNOSTICS
CRUISE CONTROL SYSTEM (w/o ETCS–i)
DI–743
1005
Author:
Date:
2003 TOYOTA TACOMA (RM1002U)
INSPECTION PROCEDURE
1
Check voltage between terminal IDL of cruise control ECU connector and body
ground.
PREPARATION:
(a)
Remove the ECU with the connector being connected.
(b)
Disconnect the ECM connector.
(c)
Turn the ignition switch ON.
CHECK:
Measure the voltage between terminal IDL of the ECU connec-
tor and the body ground when the throttle valve is fully closed
and fully opened.
OK:
Throttle Valve Position
Voltage
Fully opened
10 – 16 V
Fully closed
Below 1.5 V
OK
Proceed to next circuit inspection shown in
problem symptoms table (See page DI–730).
NG
2
Check harness and connector between ECM and throttle position sensor (See
page IN–28).
NG
Repair or replace harness or connector.
OK
3
Check throttle position sensor circuit (See page DI–272).
NG
Replace throttle position sensor.
OK
DI–744
–
DIAGNOSTICS
CRUISE CONTROL SYSTEM (w/o ETCS–i)
1006
Author:
Date:
2003 TOYOTA TACOMA (RM1002U)
4
Check throttle position sensor.
NG
Replace throttle