DTC C1A4B: Stop Light Relay Circuit [06/2015 - 11/2018]: Description
The skid control ECU (brake booster with master cylinder assembly) sends a stop light operation signal to the stop light switch assembly. When the skid control ECU (brake booster with master cylinder assembly) detects a malfunction in the stop light circuit, the driving support ECU assembly stores DTC C1A4B.
| DTC No. |
Detection Item |
DTC Detection Condition |
Trouble Area |
| C1A4B |
Stop Light Relay Circuit |
Either of the following conditions is met:
- When the power switch is on (IG), the IG1 terminal voltage is between 11 and 14 V and the stop light illumination output signal (STPO) is output, the signal is not received at terminal STP2 for 0.3 seconds or more.
- When the power switch is on (IG), the IG1 terminal voltage is between 11 and 14 V and the stop light illumination output signal (STPO) is not output, the signals received at terminals STP and STP2 are different for 0.3 seconds or more.
|
- Lighting system
- Electronically controlled brake system
- Harness or connector
- Stop light switch assembly
- Driving support ECU assembly
|
| |
Vehicle Condition |
| Pattern 1 |
Pattern 2 |
| Diagnosis Condition |
IG1 terminal voltage is 11 to 14 V |
◦ |
◦ |
| Stop Light illumination output (STPO) ON |
◦ |
- |
| Stop Light illumination output (STPO) OFF |
- |
◦ |
| Malfunction Status |
No signal input to STP2 terminal |
◦ |
- |
| Signals input to STP and STP2 terminals do not match |
- |
◦ |
| Malfunction Time |
0.3 seconds or more |
0.3 seconds or more |
| Number of Trips |
- |
- |