Code B552, Keep Alive Memory Error (TORONADO)

Fig 1: Code B552 Flowchart, Keep Alive Memory Error (Toronado)

NOTE: Code B552 indicates that the "Keep Alive" or "Long Term" memory in the BCM has been reset. This will be the case whenever power is removed from the BCM (such as disconnecting the battery cables, disconnecting BCM power connector, or losing crank signal to the BCM). This code should be cleared from memory after restoring the BCM power supply.

Fig 2: Code B552, Keep Alive Memory Error (Toronado)

Fig 3: Code B552 Schematic, Keep Alive Memory Error (Toronado)

Code B552 does not normally indicate a fault, but is a normal occurrence anytime the power to the BCM has been interrupted. Code B552 cannot be cleared from memory in the normal manner. Code B552 can only be cleared if it is not "Current". Under normal, or "No Trouble Found" conditions, the code will become "History" by the following: Key in "LOCK", wait 5 seconds, turn key on, and then reenter diagnostics. This code should now be "History", and can be cleared in the normal manner.

The code will also set if the following conditions are met: Ignition in "Crank" and no system voltage signal to BCM terminal 1C9. The purpose of the crank circuit is to signal the BCM to shut off when cranking so that voltage variations that are normal during starting do not affect the electronic devices.

This code could also set during cranking if the system voltage drops below 8 volts at BCM terminal 1C9. Possible causes for this are: Faulty charging system, faulty starter system, extreme cold weather and/or jump starting the vehicle.

This step is to change Code B552 from "Current" to "History".
Checks to see if Code B552 was set due to a fault in the crank signal circuit.
By removing the fuel pump fuse, the engine will not start and voltage during cranking can be observed.
Checks for sufficient system voltage at BCM terminal 1C9. System voltage must not drop below 8 volts during cranking.
If the fuse is blown, check for a ground in circuit 806. A blown fuse will appear the same at the BCM as an open in circuit 806.