B2528

DTC B2528 Horn Relay Circuit Shorted To Voltage:

CIRCUIT DESCRIPTION
The Body Control Module (BCM) sounds the horns for the alarm feature. When the BCM grounds circuit 28, it energizes the horn relay and causes the horns to sound. The BCM monitors the voltage level in Circuit 28. When the BCM energizes the horn relay, the voltage level in circuit 28 should be low. When the horn relay is de-energized, the voltage in circuit 28 should be high.

CONDITIONS FOR SETTING THE DTC
^ BCM detects a high voltage level (i.e. short to B+ or BCM shorted to B+ internally) in the horn control circuit (circuit 28).
^ The BCM tests for this condition when attempting to energize the horn relay during an alarm activation.
^ All conditions must be present for more than 0.08 seconds.

ACTION TAKEN WHEN THE DTC SETS
^ The BCM stores DTC B2528 in memory.
^ The BCM turns off its output to the horn relay.

CONDITIONS FOR CLEARING THE DTC
^ When the ignition switch is turned from the LOCK or OFF position to the RUN position, a current DTC B2528 is always cleared. If a short to B+ is still present in circuit 28 when the BCM attempts to ground circuit 28 during an alarm function, DTC B2528 will reset as a current DTC.
^ A history DTC will clear after 100 consecutive ignition cycles if the condition for the malfunction is no longer present.
^ Using a scan tool.

DIAGNOSTIC AIDS
^ The following conditions may cause an intermittent malfunction to occur:
- An intermittent short to B+ in circuit 28.
- The BCM is shorted to B+ internally.
- The horn relay coil is shorted to B+ internally.
^ If the BCM is shorted to voltage internally, or if circuit 28 is shorted to voltage, the horn will remain off at all times.
^ If the DTC is a history DTC, the problem may be intermittent. Try performing the tests shown while moving wiring and connectors, this can often cause the malfunction to reappear.
^ DTC P1626 will set in the Powertrain Control Module (PCM) when the ignition switch is in the RUN position with the BCM disconnected. When BCM diagnostics and repairs are completed, refer to the Engine Controls for additional information on PCM related DTCs. Powertrain Management

TEST DESCRIPTION
Numbers below refer to the step numbers on the diagnostic table.
2. Checks for a short to B+ in circuit 28.
3. Cheeks the coil side of the horn relay for proper resistance values.
5. Determines whether the malfunction is intermittent or the BCM is faulty.