Technical Service Bulletins

Remote start parasitic draw

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Remote start parasitic draw

Some 2008 Toyota 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.

Toyota recommends using a Fluke 88 digital multimeter (or equivalent) and the GR8 battery diagnostic station (SPX/OTC P/N 00002-MCGR8).

NOTE: The Remote E/G Starter ECU is available under part number 08190-42830.

Use the procedure listed here to assist with the diagnosis of excessive parasitic battery draw to correctly identify if the RES 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 to ease removal from the battery negative 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).
    1. Turn the key to IG-ON, then back off to OFF. Remove the key from the ignition switch and close all doors.
    2. Using the remote control, press the unlock button one time. Open and close the driver door within 30 seconds.
    3. Wait for five minutes.
    4. Place the negative terminal of the multimeter to the negative battery post, and place the positive terminal of the multimeter to the clamp of the negative terminal battery cable. Clip type leads will ensure continuous contact with terminals.
    5. Remove the negative terminal clamp from the negative terminal post of the battery. The terminals of the multimeter must be in continuous contact before and during removal. Otherwise, the ECUs will wake up and you must return to Step 3A.
    6. Record the parasitic current draw. If the current value is over 75mA, go to Step 4. If the current value is less than 75mA, then the RES ECU has no problem and this TSB does not apply. Inspect for other causes of excessive current draw.
  4. Measure the vehicle standby current (without RES ECU).
    1. Disassemble the vehicle to gain access to the RES ECU (refer to the service manual or TIS).
    2. Disconnect the 20P connector from the RES ECU.
    3. Repeat Steps 3a-3f.
    4. Record the parasitic current draw. If the current value is over 75mA, then the RES ECU is not the root cause. If the current value is less than 75mA, 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. 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 while replacing the cable.
  6. Re-initialize any affected power systems. Refer to TSB No. PD014-06 or PD010-07, “Power System Initialization During PDS.”


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