C1249 Open in Stop Light Switch Circuit

1. Remove the STOP fuse from the No. 2 relay block.
2. Measure the resistance according to the value (s) in the table below.
   
   
   Standard resistance:

   Tester Connection	Condition	Specified Condition
   STOP (7.5 A) fuse	Always	Below 1 Ω

REPLACE STOP FUSE

[2] CHECK STOP LIGHT OPERATION

1. Install the STOP fuse.
2. Check that the stop light comes on when the brake pedal is depressed, and goes off when the brake pedal is released.
   
   OK:
   　

   Condition	Illumination Condition
   Brake pedal depressed	ON
   Brake pedal released	OFF

Go to step 7

[3] INSPECT SKID CONTROL ECU (STP TERMINAL)

1. Disconnect the skid control ECU connector.
2. Measure the voltage according to the value (s) in the table below.
   
   
   Standard voltage: 　

   Tester Connection	Switch Condition	Specified Condition
   S13-1 (STP) - Body ground	Stop light switch ON (Brake pedal depressed)	16 to 32 V
   S13-1 (STP) - Body ground	Stop light switch OFF (Brake pedal released)	Below 3 V

　

REPAIR OR REPLACE HARNESS OR CONNECTOR (STP CIRCUIT)

[4] INSPECT SKID CONTROL ECU (IG1 TERMINAL)

1. Turn the ignition switch to the ON position.
2. Measure the voltage according to the value (s) in the table below.
   
   
   　 Standard voltage: 　

   Tester Connection	Switch Condition	Specified Condition
   S13-7 (IG) - Body ground	Ignition switch ON	20 to 32 V

REPAIR OR REPLACE HARNESS OR CONNECTOR (IG CIRCUIT)

[5] INSPECT SKID CONTROL ECU GND TERMINAL)

1. Turn the ignition switch off.
2. Disconnect the skid control ECU connectors.
3. Measure the resistance according to the value (s) in the table below.
   
   
   
   Standard resistance: 　

   Tester Connection	Condition	Specified Condition
   S14-2 (GND1) - Body ground	Always	Below 1 Ω
   S14-3 (GND2) - Body ground	Always	Below 1 Ω
   S11-15 (GND3) - Body ground	Always	Below 1 Ω
   S11-14 (GND4) - Body ground	Always	Below 1 Ω

　

REPAIR OR REPLACE HARNESS OR CONNECTOR (GND CIRCUIT)

[6] RECONFIRM DTC

1. Reconnect the skid control ECU connectors.
2. Clear the DTC (See Pub. No. S1-YXZE05A, page 05-108).
3. Start the engine.
4. Depress the brake pedal several times to test the stop light circuit.
5. Check if the same DTC is recorded (See Pub. No. S1-YXZE05A, page 05-108).
   
   Result: 　

   Result	Proceed to
   DTC (C1249) is not output	A
   DTC (C1249) is output	B

   
   
   If troubleshooting has been carried out according to the Problem Symptoms Table, refer back to the table and proceed to the next step (See PROBLEM SYMPTOMS TABLE).
   

REPLACE SKID CONTROL ECU

CHECK FOR INTERMITTENT PROBLEMS (SYMPTOM SIMULATION) (See DIAGNOSIS SYSTEM)

1. Disconnect the stop light switch connector.
2. Measure the voltage according to the value (s) in the table below.
   　 　
   
   Standard voltage:

   Tester Connection	Condition	Specified Condition
   S15-2 - Body ground	Always	20 to 32 V

REPAIR OR REPLACE HARNESS OR CONNECTOR (POWER SOURCE CIRCUIT)

[8] INSPECT STOP LIGHT SWITCH

1. Measure the resistance according to the value (s) in the table below.
   
   
   Standard resistance: 　

   Tester Connection	Switch Condition	Specified Condition
   1-2	Switch pin free	Below 1 Ω
   1-2	Switch pin pushed in	10 kΩ or higher

REPLACE STOP LIGHT SWITCH

[9] CHECK HARNESS AND CONNECTOR (SKID CONTROL ECU - STOP LIGHT SWITCH)

　

1. Disconnect the skid control ECU connector.
2. Measure the resistance according to the value (s) in the table below.

   

   Standard resistance:

   Tester Connection	Condition	Specified Condition
   S13-1 (STP) - S15-1	Always	Below 1 Ω
   S13-1 (STP) - Body ground	Always	10 kΩ or more

　

REPAIR OR REPLACE HARNESS OR CONNECTOR

[10] RECONFIRM DTC

1. Reconnect the skid control ECU connector and the stop light switch connector.
2. Clear the DTC (See Pub. No. S1-YXZE05A, page 05-108).
3. Start the engine.
4. Depress the brake pedal several times to test the stop light circuit.
5. Check if the same DTC is recorded (See Pub. No. S1-YXZE05A, page 05-108).
   
   Result:

   Result	Proceed to
   DTC (C1249) is not output	A
   DTC (C1249) is output	B

   
   
   If troubleshooting has been carried out according to the Problem Symptoms Table, refer back to the table and proceed to the next step (See PROBLEM SYMPTOMS TABLE).
   

　

A REPLACE SKID CONTROL ECU

B INSPECT LIGHTING SYSTEM (STOP LIGHT CIRCUIT)

1. Confirm the DTC C1249 is inactive

   • 　Start the engine and let it idling condition.
   • Verify the DTC C1249 is inactive.

   

   DTC Clear

   • Clear the DTC with Hino DX
   • Confirm the same DTC is not reoccurred

   

C1249 is reoccur: Return to first process Other DTC appear: Refer to concerned Trouble shooting

Complete