ECU Power Source Circuit
CAUTION / NOTICE / HINT
NOTICE:
Inspect the fuses for circuits related to this system before performing the following inspection procedure.
PROCEDUREINSPECT BATTERY
(a) Check the battery voltage.
Standard voltage:
11 to 14 V
| NG | ![]() |
CHECK OR REPLACE CHARGING SYSTEM OR BATTERY |
|
CHECK HARNESS AND CONNECTOR (+B AND IG TERMINAL)
(a) Turn the ignition switch off.
(b) Disconnect the 4 wheel drive control ECU connector. |
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(c) Measure the voltage according to the value(s) in the table below.
Standard Voltage:
Tester Connection | Switch Condition | Specified Condition |
|---|---|---|
F13-21 (+B) - Body ground |
Always |
11 to 14 V |
F12-4 (IG) - Body ground |
Ignition switch ON |
11 to 14 V |
*a |
Front view of wire harness connector (to 4 Wheel Drive Control ECU) |
| NG | ![]() |
REPAIR OR REPLACE HARNESS OR CONNECTOR (+B AND IG CIRCUIT) |
|
CHECK HARNESS AND CONNECTOR (GND TERMINAL)
(a) Turn the ignition switch off.
(b) Measure the resistance according to the value(s) in the table below. Standard Resistance:
|
![]() |
| OK | ![]() |
PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE |
| NG | ![]() |
REPAIR OR REPLACE HARNESS OR CONNECTOR (GND CIRCUIT) |
Test yourself
A quick Toyota Tacoma quiz: every answer comes with an explanation and a link to the manual page.
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