[Previous][Next]
DTC B1722: Immobilizer-antenna fail
 
 
cautionWhenever the ECU is replaced, ensure that the power supply circuit, the ground circuit and the communication circuit are normal.
 
 
TROUBLE JUDGMENT
DTC No. B1722 is stored when the ETACS-ECU cannot communicate with the ignition key because of defective key ring antenna (antenna wire).
 
 
 
TECHNICAL DESCRIPTION (COMMENT)
Current trouble
  • The wiring harness wire or connectors between the ETACS-ECU and the key ring antenna may have loose, corroded, or damage terminals, or terminals pushed back in the connector, or the key ring antenna (antenna wire) may be defective.
Past trouble
  • If DTC No. B1722 is stored as a past trouble, it is possible that there were defective wiring harnesses, defective connectors or defective antennas before.
 
 
 
TROUBLESHOOTING HINTS
  • The key ring antenna (antenna wire) may be defective.
  • The ETACS-ECU may be defective.
  • The wiring harness or connectors may have loose, corroded, or damaged terminals, or terminals pushed back in the connector.
 
 
 
 
DIAGNOSIS
Required Special Tools:
  • MB991223: Harness Set
  • MB992006: Extra Fine Probe
STEP 1. Check the key reminder switch (ignition key ring antenna).
(1) Disconnect the key reminder switch (ignition key ring antenna) connector.
(2) Take the measurements below at component-side connector.
  • There should be continuity between terminals 3 and 7.
OK: The resistance should be 2 ohm or less.
Is the check result satisfactory?
Go to Step 2.
Replace the key reminder switch (ignition key ring antenna), and then go to Step 4.
 
STEP 2. Check of short to power supply, short to ground, and open circuit in ANT+, ANT- line between ETACS-ECU connector and key reminder switch connector.
Is the check result normal?
Go to Step 3.
Repair the connector(s) or wiring harness, and then go to Step 3.
 
STEP 3. Recheck for diagnostic trouble code.
(1)
cautionTo prevent damage to scan tool (M.U.T.-III), always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool (M.U.T.-III).
Connect scan tool (M.U.T.-III). Refer to "How to connect the Scan Tool (M.U.T.-III) ."
(2) Turn the ignition switch to the "LOCK" (OFF) position once, and then turn it to the "ON" position again.
(3) Check if DTC No. B1722 is stored as a current trouble.
Is DTC No. B1722 set as a current trouble?
Replace the key reminder switch (ignition key ring antenna), and then go to Step 4.
If DTC No. B1722 is stored as a past trouble, erase the DTC that is stored as a past trouble, and the diagnosis is complete.
 
STEP 4. Recheck for diagnostic trouble code.
(1) Turn the ignition switch to the "LOCK" (OFF) position once, and then turn it to the "ON" position again.
(2) Check if DTC No. B1722 is stored as a current trouble.
Is DTC No.B1722 set as a current trouble?
Replace the ETACS-ECU. After registering the ID codes, return to Step 1.
If DTC No. B1722 is stored as a past trouble, erase the DTC that is stored as a past trouble, and the diagnosis is complete.