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Pinpoint Test E: DTC B1681




Anti-Theft

Pinpoint Tests

Pinpoint Test E: DTC B1681

Refer to Wiring Diagram Set 112 (Escape/Mariner, Escape Hybrid/Mariner Hybrid), 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) on fuse 36 (5A). The PATS transceiver and the Instrument Cluster (IC) communicate on the TX and RX circuits. The IC compares the key code stored in memory and sends a message to the PCM to enable the starter and fuel injectors if the key code is correct.

- 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 between the PATS transceiver and the IC, or circuits to the PATS transceiver. 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 will result in false resistance readings. Refer to Battery, Mounting and Cables Battery Disconnect.

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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. CLEAR the DTCs. CYCLE the ignition. REPEAT the self-test. If not OK, Refer to the Wiring Diagrams to identify the possible causes of the circuit short. 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 GD112 (BK/GN), harness side and ground.





- Is the resistance less than 5 ohms?

Yes
CONNECT the negative battery cable. 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 ensuring 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: PATS Transceiver C252.
- Ignition ON.
- Measure the voltage by back-probing between the PATS transceiver C252-4, circuit VRT23 (VT/GY), 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 VRT23 (VT/GY), 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. TEST the system for normal operation.

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 IC C220-3, circuit VRT23 (VT/GY), harness side and the PATS transceiver C252-4, circuit VRT23 (VT/GY), 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. TEST the system for normal operation.

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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 ensuring 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 back-probing between the PATS transceiver C252-3, circuit VRT24 (YE/OG), 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. TEST the system for normal operation.

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 C220-4, circuit VRT24 (YE/OG), 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 C220-4, circuit VRT24 (YE/OG), 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. TEST the system for normal operation.

No
REPAIR the circuit. CLEAR the DTCs. CYCLE the ignition. REPEAT the self-test. TEST the system for normal operation.

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E9 CHECK THE PATS TRANSCEIVER TRANSMIT CIRCUIT FOR AN OPEN

- Disconnect: PATS Transceiver C252.
- Measure the resistance between the IC C220-4, circuit VRT24 (YE/OG), harness side and the PATS transceiver C252-3, circuit VRT24 (YE/OG), 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. TEST the system for normal operation.

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E10 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 ensuring 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.
- Connect the scan tool.
- Ignition ON.
- Enter the following diagnostic mode on the scan tool: IC DataLogger.
- Trigger the IC active command TRANSMIT SIGNAL to on.

- NOTE: The voltage only reads for a very short period of time. Make sure to monitor the meter closely while triggering the active command on.

- Measure the voltage by back-probing between the PATS transceiver C252-3, circuit VRT24 (YE/OG), 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. TEST the system for normal operation.

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 VRT24 (YE/OG), harness side and ground.





- Is any voltage indicated?

Yes
REPAIR the circuit. CLEAR the DTCs. CYCLE the ignition. REPEAT the self-test. TEST the system for normal operation.

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 Instrumentation, Message Center, and Warning Chimes Instrument Cluster (IC). RESET the parameters in both the IC and the PCM. REFER to Passive Anti-Theft System (PATS) Parameter Reset Passive Anti-Theft System (PATS) Parameter Reset. PROGRAM the PATS keys into the new IC. REFER to Integrated Keyhead Transmitter (IKT) Key Programming Using Diagnostic Equipment Using Diagnostic Equipment. CYCLE the ignition. 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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