Technical Service Bulletins

Scion battery drain

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Scion battery drain

Some 2008 Scion xB and xD vehicles equipped with a remote engine starter (RES) may exhibit a discharged battery condition after short term storage due to parasitic draw. Use the procedure in this TSB to assist with diagnosis of excessive parasitic battery draw to correctly identify if the remote engine starter ECU is the cause.

  1. Before proceeding, determine the battery state of charge using the GR8 battery diagnostic station. If necessary, charge or replace the battery.
  2. Loosen the negative battery terminal of the battery cable from the negative battery post. Do not remove the terminal completely. Make sure that there is continuous electrical contact at all times.
  3. Measure the vehicle standby current (initial). Turn the key to “IG-ON,” then back to the “OFF” position. Close all doors. Using the remote control, press the unlock button one time. Open and close the driver’s door within 30 seconds, and then wait for five minutes. Place the negative terminal of the multimeter to the battery negative post and the multimeter positive terminal to the clamp of the negative battery cable terminal (use clip type leads to ensure continuous contact). Remove the negative terminal clamp from the negative battery post. The terminals of the multimeter must be in continuous contact before and during removal. Otherwise, the ECUs will wake up, and you’ll need to start over. Record the parasitic current draw. If the current value is over 75 mA, go to Step 4. If current value is less than 75 mA, then the RES ECU has no problem and this TSB does not apply.
  4. Measure the vehicle standby current (without RES ECU.

a  Disassemble the vehicle to gain access to the RES ECU. Refer to TIS, applicable model and year RES installation instructions.

b. Disconnect the 20P connector from the RES ECU.

c. Repeat Step 3.

d. Record the parasitic current draw. If the current draw is over 75 mA, then the RES ECU is not the root cause. Inspect other causes of excessive current draw. If the current value is less than 75 mA, order a new RES ECU and replace.

        5 Reassemble and reconnect any disconnected connectors. Verify that the panels fit together properly with no uneven gaps between them. Position the negative battery cable at the original factory position and tighten the nut to 36 in-lbf. Do not touch the positive terminal with any tool when replacing the cable.

        6. Re-initialize any affected power systems. Refer to PD010-07 “Power System Initialization During PDS.”

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