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Pinpoint Test E: DTC B1681




Anti-Theft

Pinpoint Tests

Pinpoint Test E: DTC B1681

Refer to Wiring Diagram Set 112, Passive Anti-Theft System for schematic and connector information. Diagrams By Number

Normal Operation

The Passive Anti-Theft System (PATS) transceiver receives voltage from the Smart Junction Box (SJB) fuse 36 (5A) on circuit CBP36 and is grounded on circuit GD133. The PATS transceiver and the Instrument Cluster (IC) communicate on the TX and RX circuits VRT23 and VRT24. The IC compares the key code stored in memory and sends a message to the PCM to enable the starter if the key code is correct. If there is an issue with the fuse, wiring, PATS transceiver or the IC itself, the IC sets DTC B1681 and also sends a PATS disable message to the PCM. The PCM will not allow the fuel injectors or the starter to operate.

- DTC B1681 (PATS Transceiver Module Signal Is Not Received) - sets when the PATS transceiver signal is not received by the IC. This DTC can be caused by circuits to the PATS transceiver, circuits between the PATS transceiver and the IC, the PATS transceiver or the IC. This can also be caused by using the incorrect PATS transceiver part number.

This pinpoint test is intended to diagnose the following:

- Fuse
- Wiring, terminals or connectors
- PATS transceiver
- IC



PINPOINT TEST E: DTC B1681

NOTICE: Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may damage the connector.

NOTE: Failure to disconnect the battery when instructed will result in false resistance readings. Refer to Battery.

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E1 CHECK THE PATS TRANSCEIVER POWER CIRCUIT FOR VOLTAGE


- Ignition OFF.
- Disconnect: PATS Transceiver C252.
- Ignition ON.
- Measure the voltage between the PATS transceiver C252-1, circuit CBP36 (BU/BN), harness side and ground.




- Is the voltage greater than 10 volts?

Yes
GO to E2.

No
VERIFY the SJB fuse 36 (5A) is OK. If OK, REPAIR the circuit for an open. If not OK, REFER to the Wiring Diagrams to identify the possible causes of the circuit short. CLEAR the DTCs. CYCLE the ignition. REPEAT the self-test. Diagrams By Number

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E2 CHECK THE PATS TRANSCEIVER GROUND CIRCUIT FOR AN OPEN


- Ignition OFF.
- Disconnect: Negative Battery Cable.
- Measure the resistance between the PATS transceiver C252-2, circuit GD133 (BK), harness side and ground.




- Is the resistance less than 5 ohms?

Yes
GO to E3.

No
REPAIR the circuit. CONNECT the negative battery cable. CLEAR the DTCs. CYCLE the ignition. REPEAT the self-test.

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E3 CHECK THE PATS TRANSCEIVER RECEIVE CIRCUIT FOR VOLTAGE


NOTICE: This pinpoint test step directs testing circuits using a back-probe method. Use the special back-probe tool specified in the tool list. Do not force test leads or other probes into connectors. Adequate care must be exercised to avoid connector terminal damage while making sure that good electrical contact is made with the circuit or terminal. Failure to follow these instructions may cause damage to wiring, terminals, or connectors and subsequent electrical faults.

- Connect: Negative Battery Cable.
- Connect: PATS Transceiver C252.
- Ignition ON.
- Measure the voltage by backprobing between the PATS transceiver C252-4, circuit VRT24 (YE/OG), harness side and ground.




- Is the voltage greater than 8 volts?

Yes
GO to E6.

No
GO to E4.

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E4 CHECK THE PATS TRANSCEIVER RECEIVE CIRCUIT FOR A SHORT TO GROUND


- Ignition OFF.
- Disconnect: IC C220.
- Disconnect: PATS Transceiver C252.
- Measure the resistance between the PATS transceiver C252-4, circuit VRT24 (YE/OG), harness side and ground.




- Is the resistance greater than 10,000 ohms?

Yes
GO to E5.

No
REPAIR the circuit. CLEAR the DTCs. CYCLE the ignition. REPEAT the self-test.

If DTC B1681 is retrieved again, GO to E12.

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E5 CHECK THE PATS TRANSCEIVER RECEIVE CIRCUIT FOR AN OPEN


- Measure the resistance between the PATS transceiver C252-4, circuit VRT24 (YE/OG), harness side and the IC C220-16, circuit VRT24 (YE/OG), harness side.




- Is the resistance less than 5 ohms?

Yes
GO to E12.

No
REPAIR the circuit. CLEAR the DTCs. CYCLE the ignition. REPEAT the self-test.

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E6 CHECK THE PATS TRANSCEIVER TRANSMIT CIRCUIT FOR VOLTAGE


NOTICE: This pinpoint test step directs testing circuits using a back-probe method. Use the special back-probe tool specified in the tool list. Do not force test leads or other probes into connectors. Adequate care must be exercised to avoid connector terminal damage while making sure that good electrical contact is made with the circuit or terminal. Failure to follow these instructions may cause damage to wiring, terminals, or connectors and subsequent electrical faults.

NOTE: Replacement of the PATS transceiver does not require the PATS keys to be programmed into the IC again.

- Measure the voltage by backprobing between the PATS transceiver C252-3, circuit VRT23 (VT/GY), harness side and ground.




- Is the voltage greater than 8 volts?

Yes
INSTALL a new PATS transceiver. REFER to Passive Anti-Theft System (PATS) Transceiver Service and Repair. CLEAR the DTCs. CYCLE the ignition. REPEAT the self-test.

If DTC B1681 is retrieved again, GO to E12.

No
GO to E7.

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E7 CHECK THE PATS TRANSCEIVER TRANSMIT CIRCUIT FOR A SHORT TO GROUND WITH THE PATS TRANSCEIVER CONNECTED


- Ignition OFF.
- Disconnect: IC C220.
- Measure the resistance between the IC C220-15, circuit VRT23 (VT/GY), harness side and ground.




- Is the resistance greater than 10,000 ohms?

Yes
GO to E9.

No
GO to E8.

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E8 CHECK THE PATS TRANSCEIVER TRANSMIT CIRCUIT FOR A SHORT TO GROUND WITH THE PATS TRANSCEIVER DISCONNECTED


NOTE: Replacement of the PATS transceiver does not require the PATS keys to be programmed into the IC again.

- Disconnect: PATS Transceiver C252.
- Measure the resistance between the IC C220-15, circuit VRT23 (VT/GY), harness side and ground.




- Is the resistance greater than 10,000 ohms?

Yes
INSTALL a new PATS transceiver. REFER to Passive Anti-Theft System (PATS) Transceiver Service and Repair. CLEAR the DTCs. CYCLE the ignition. REPEAT the self-test.

No
REPAIR the circuit. CLEAR the DTCs. CYCLE the ignition. REPEAT the self-test.

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E9 CHECK THE PATS TRANSCEIVER TRANSMIT CIRCUIT FOR AN OPEN


- Disconnect: PATS Transceiver C252.
- Measure the resistance between the PATS transceiver C252-3, circuit VRT23 (VT/GY), harness side, and the IC C220-15, circuit VRT23 (VT/GY), harness side.




- Is the resistance less than 5 ohms?

Yes
GO to E10.

No
REPAIR the circuit. CLEAR the DTCs. CYCLE the ignition. REPEAT the self-test.

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E10 CHECK THE PATS TRANSCEIVER TRANSMIT CIRCUIT FOR VOLTAGE WITH THE ACTIVE COMMAND ON


NOTICE: This pinpoint test step directs testing circuits using a back-probe method. Use the special back-probe tool specified in the tool list. Do not force test leads or other probes into connectors. Adequate care must be exercised to avoid connector terminal damage while making sure that good electrical contact is made with the circuit or terminal. Failure to follow these instructions may cause damage to wiring, terminals, or connectors and subsequent electrical faults.

NOTE: Replacement of the PATS transceiver does not require the PATS keys to be programmed into the IC again.

- Connect: PATS Transceiver C252.
- Connect: IC C220.
- Ignition ON.
- Enter the following diagnostic mode on the scan tool: IC DataLogger.
- Trigger the active command TRANSMIT to ON.
- NOTE: The IC may only supply the signal voltage momentarily. It is important to monitor the meter while triggering the active command on.
- Measure the voltage by backprobing between the PATS transceiver C252-3, circuit VRT23 (VT/GY), harness side and ground.




- Is the voltage less than 5 volts?

Yes
INSTALL a new PATS transceiver. REFER to Passive Anti-Theft System (PATS) Transceiver Service and Repair. CLEAR the DTCs. CYCLE the ignition. REPEAT the self-test.

No
GO to E11.

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E11 CHECK THE PATS TRANSCEIVER TRANSMIT CIRCUIT FOR A SHORT TO VOLTAGE


- Ignition OFF.
- Disconnect: IC C220.
- Disconnect: PATS Transceiver C252.
- Ignition ON.
- Measure the voltage between the PATS transceiver C252-3, circuit VRT23 (VT/GY), harness side and ground.




- Is any voltage indicated?

Yes
REPAIR the circuit. CLEAR the DTCs. CYCLE the ignition. REPEAT the self-test.

No
GO to E12.

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E12 CHECK FOR CORRECT IC OPERATION


- Disconnect the IC connector.
- Check for:
- corrosion
- damaged pins
- pushed-out pins
- Connect the IC connector and make sure it seats correctly.
- Operate the system and verify the concern is still present.
- Is the concern still present?

Yes
INSTALL a new IC. REFER to Instrument Panel, Gauges and Warning Indicators. RESET the parameters in the IC and the PCM. REFER to Passive Anti-Theft System (PATS) Parameter Reset Passive Anti-Theft System (PATS). PROGRAM the PATS keys into the IC. REFER to Key Programming Using Diagnostic Equipment Using Diagnostic Equipment. REPEAT the self-test.

No
The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector. CLEAR the DTCs. CYCLE the ignition. REPEAT the self-test.

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