DTC Troubleshooting: U3003-16(Electric Servo Brake Control Unit)

DTC U3003-16  : Electric Servo Brake Control Unit Power Source Circuit (+B) Low Voltage

NOTE: Before you troubleshoot, review the general troubleshooting information .

DTC (Electric servo brake)

1. Problem verification

   -1. Turn the vehicle to the ON mode.

   -2. Clear the DTCs with the HDS.

   -3. Turn the vehicle to the OFF (LOCK) mode, and then to the ON mode.

   -4. Wait for 10 seconds or more.

   -5. Check for DTCs with the HDS.

   DTC Description	DTC	Freeze Frame
   U3003-16 Electric Servo Brake Control Unit Power Source Circuit (+B) Low Voltage

   Is DTC U3003-16 indicated?

   YES 

   The failure is duplicated. Go to step 2.

   NO 

   Intermittent failure, the system is OK at this time. Refer to intermittent failures troubleshooting . If the freeze data/on-board snapshot of this DTC is recorded, try to reproduce the failure under the same conditions with the Freeze data/on-board snapshot.

2. 12 volt battery voltage check

   -1. Check the parameter(s) below with the HDS.

   Signal	Current conditions
   	Value	Unit
   BATTERY VOLTAGE

   -2. Using a voltmeter, measure and note the voltage across the 12 volt battery terminals.

   -3. Compare the voltage noted in step 2-1 to the voltage in step 2

   Is the difference between the two voltage readings less than 3 V?

   YES 

   Go to step 3.

   NO 

   Check the 12 volt battery , and check electric powertrain system DTCs .

3. Fuse check

   -1. Turn the vehicle to the OFF (LOCK) mode with driver's door open.

   -2. Wait 3 minutes.

   NOTE:  Do not close the driver's door.

   -3. Check the following fuse.

   Fuse

   No. B2-2

   Is the fuse OK?

   YES 

   The fuse is OK. Reinstall the fuse, then go to step 4.

   NO 

   Replace the fuse. If the fuse blows again, repair a short to ground in the No. B2-2 fuse circuit.

4. Open wire check (+B ESB line)

   -1. Disconnect the following connector.

   Electric servo brake control unit 22P connector

   -2. Measure the voltage between test points 1 and 2.

   Test condition	Vehicle OFF (LOCK) mode
   	Electric servo brake control unit 22P connector: disconnected
   Test point 1	Electric servo brake control unit 22P connector No. 5
   Test point 2	Body ground

   Is there battery voltage?

   YES 

   Check for loose terminals and poor connections in the electric servo brake control unit 22P connector. Check for any authorized service information related to the DTCs or symptoms you are troubleshooting. If they are OK, replace the electric servo brake control unit/pedal feel simulator .

   NO 

   Repair an open in the +B ESB wire between the electric servo brake control unit and the under-hood fuse/relay box.