DTC B1951

Precautions: Precautions for Headlight Auto Leveling System Service · Precautions for Body, Cab and Accessories · General safety (00)

NOTE:

•As each terminal voltage is affected by the battery voltage, check that battery voltage is 12 V or more with ignition “ON”.
•Before performing, check that related fuses of headlight auto leveling control module power circuit have not blown out.
If any fuse has blown out, replace the fuse and check circuits connected to the blown fuse for short circuit to ground.

DTC Detecting Condition and Trouble Area

DTC detecting condition	Trouble area
B1951: Ignition Power Supply Voltage Data Malfunction Any of the following condition is met. •Headlight auto leveling control module power supply circuit voltage is higher than 16.4 V for 10 sec. •Headlight auto leveling control module power supply circuit voltage is lower than 9.3 V for 10 sec.	•Headlight auto leveling control module power supply circuit •Headlight auto leveling control module •Charging system

Circuit Diagram

[A]:	J/B connector (View: [a])	1.	J/B	4.	Headlight auto leveling control module
[B]:	Headlight auto leveling control module connector (View: [a])	2.	“BACK” fuse	5.	Voltage regulator circuit
A1:	Headlight auto leveling control module power supply circuit	3.	To IG1 relay

DTC Confirmation Procedure

1)Run engine at idle speed for 10 sec. or more.

DTC Troubleshooting

Step	Action	Yes	No
1	DTC check 1)Clear DTC. 2)Set ignition “OFF”. 3)Disconnect “E18” and “E336” connectors. 4)Check for proper terminal connections to “E18” and “E336” connectors. 5)If connections are OK, connect “E18” and “E336” connectors securely. 6)Perform “DTC Confirmation Procedure” and recheck DTC. Is DTC B1951 still detected?	Go to Step 2.	Intermittent trouble.
2	Headlight auto leveling control module circuit check 1)Set ignition “OFF”. 2)Disconnect “E18” and “E336” connectors. 3)Check “A1” circuit between “E18” connector and “E336” connector for open circuit, short to ground or short to power supply. Is check result OK?	Go to Step 3.	Repair or replace defective harness and recheck DTC.
3	Headlight auto leveling control module power supply voltage check 1)Check “A1” circuit voltage with engine speed at 3,000 rpm. Is voltage 10 – 14 V?	Replace headlight auto leveling control module and recheck DTC.	Check charging system. •M16A model: •D16AA model: