DTC P1551: Brake SW Signal Correlation Error
- Check the ''On Board Diagnostic (OBD) System Check''.
Was the ''OBD System Check'' performed?
YES – Go to step 2.
NO – Go to OBD System Check. 
- Turn the ignition switch OFF.
- Check the brake lamp (10A) fuse.
Is the brake lamp fuse OK?
YES – Go to step 4.
NO – Replace the fuse.
- Disconnect the ECM connector A.
- Turn the ignition switch ON (II).
- Connect the DVM to the ECM terminal No. 59 and body ground.
- Press the brake pedal.
Is there battery voltage?
YES – Go to step 15.
NO – Go to step 8.
- Turn the ignition switch OFF.
- Disconnect the brake SW connector.
- Connect the DVM to the brake SW connector terminal No. 1 and No. 2 with a jumper wire.
JUMPER WIRE
Wire side of female terminals
- Turn the ignition switch ON (II).
- Connect the DVM to the ECM terminal No. 59 and body ground.
- Press the brake pedal.
Is there battery voltage?
YES – Replace the brake SW.
NO – Go to step 14.
- Measure voltage between the brake SW connector terminals No. 1 and body ground.
Wire side of female terminals
Is there battery voltage?
YES – Repair open in the wire between the brake SW and the ECM.
NO – Repair open in the wire between the brake SW and the battery.