Code No.B1156
Power supply voltage low
caution |
When replacing the ECU, always
check that the communication circuit is normal.
|
DIAGNOSTIC FUNCTION
If the system detects that +B voltage decreases, the KOS&OSS-ECU will
set diagnosis code No. B1156.
JUDGEMENT CRITERIA
Check Conditions
- The power supply mode is NOT at ON without cranking with the KOS&OSS-ECU
activated
Judgement Criterion
- +B voltage remains 9.0 V or less for at least five seconds.
PROBABLE CAUSES
- Damaged wiring harness or connector (+B line short
to earth or open circuit)
- Malfunction of KOS&OSS-ECU
- Deteriorated battery
DIAGNOSIS PROCEDURE
note |
Prior to diagnosis, check the battery. (Refer to GROUP 54A - Battery Test .)
|
STEP 1. Voltage measurement at +B connector (+B
line)
|
(1)Disconnect the connector, and measure at the wiring harness side.
|
|
(2)Turn the engine switch from "ON" position to "LOCK" (OFF) position.
|
|
(3)Measure the voltage between the +B connector (+B line) and the
body earth. OK: System voltage
|
Q.
Is the check result normal?
Go to Step 3.
Go to Step 2.
STEP 2. Check of short to earth or open circuit in +B line
between the KOS&OSS-ECU connector and the battery
Q.
Is the check result normal?
Go to Step 3.
Repair the connector(s) or wiring harness.
STEP 3. Check whether the diagnosis code is set again.
Q.
Is the diagnosis code set?
Replace the KOS&OSS-ECU and register the chassis number (Refer to
).
Intermittent malfunction is suspected (Refer to GROUP 00 - How to Use Troubleshooting/Inspection
Service Points - How to Cope with Intermittent Malfunction
).