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Home >> Mercury >> 2009 >> Grand Marquis V8-4.6L >> Repair and Diagnosis >> Accessories and Optional Equipment >> Antitheft and Alarm Systems >> Testing and Inspection >> Pinpoint Tests >> Pinpoint Test E: DTC B1681

Pinpoint Test E: DTC B1681




Anti-Theft

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 Central Junction Box (CJB) fuse 24 (10A) on circuit 1266 (RD/YE) and is grounded on circuit 676 (PK/OG). The PATS transceiver and the PCM communicate on circuits 1215 (WH/LG) and 1216 (GY/OG). The PCM compares the key code stored in memory and enables the starter 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 PCM. This DTC can be caused by circuits to the PATS transceiver, circuits between the PATS transceiver and the PCM, the PATS transceiver or the PCM.

This pinpoint test is intended to diagnose the following:

- Fuse
- PATS key
- PATS transceiver
- Wiring, terminals or connectors
- PCM



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.

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E1 CHECK THE PATS TRANSCEIVER POWER CIRCUIT 1266 (RD/YE) FOR VOLTAGE


- Ignition OFF.
- Disconnect: PATS Transceiver C2007.
- Ignition ON.
- Measure the voltage between the PATS transceiver C2007-1, circuit 1266 (RD/YE), harness side and ground.




- Is the voltage greater than 10 volts?

Yes
GO to E2.

No
VERIFY the CJB fuse 24 (10A) 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.

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E2 CHECK THE PATS TRANSCEIVER GROUND CIRCUIT 676 (PK/OG) FOR AN OPEN


- Ignition OFF.
- Measure the resistance between the PATS transceiver C2007-2, circuit 676 (PK/OG), harness side and ground.




- Is the resistance less than 5 ohms?

Yes
GO to E3.

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

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E3 CHECK THE PATS TRANSCEIVER RECEIVE CIRCUIT 1216 (GY/OG) FOR VOLTAGE


- Connect: PATS Transceiver C2007.
- Ignition ON.
- Measure the voltage by backprobing between the PATS transceiver C2007-4, circuit 1216 (GY/OG), harness side and ground.




- Is the voltage greater than 8 volts?

Yes
GO to E7.

No
GO to E4.

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E4 CHECK THE PATS TRANSCEIVER RECEIVE CIRCUIT 1216 (GY/OG) FOR A SHORT TO GROUND


- Ignition OFF.
- Disconnect: PCM C175b.
- Disconnect: PATS Transceiver C2007.
- Measure the resistance between the PATS transceiver C2007-4, circuit 1216 (GY/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 E13.

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E5 CHECK THE PATS TRANSCEIVER RECEIVE CIRCUIT 1216 (GY/OG) FOR AN OPEN


- Measure the resistance between the PCM C175b-42, circuit 1216 (GY/OG), harness side, and the PATS transceiver C2007-4, circuit 1216 (GY/OG), harness side.




- Is the resistance less than 5 ohms?

Yes
GO to E6.

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

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E6 CHECK THE PATS TRANSCEIVER RECEIVE CIRCUIT 1216 (GY/OG) FOR A SHORT TO GROUND WITH THE
PATS TRANSCEIVER CONNECTED


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

- Connect: PATS Transceiver C2007.
- Measure the resistance between the PCM C175b-42, circuit 1216 (GY/OG), harness side and ground.




- Is the resistance greater than 10,000 ohms?

Yes
GO to E13.

No
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.

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E7 CHECK THE PATS TRANSCEIVER TRANSMIT CIRCUIT 1215 (WH/LG) FOR VOLTAGE


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

- Measure the voltage by backprobing between the PATS transceiver C2007-3, circuit 1215 (WH/LG), 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 E13.

No
GO to E8.

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E8 CHECK THE PATS TRANSCEIVER TRANSMIT CIRCUIT 1215 (WH/LG) FOR A SHORT TO GROUND WITH THE
PATS TRANSCEIVER CONNECTED


- Ignition OFF.
- Disconnect: PCM C175b.
- Measure the resistance between the PCM C175b-22, circuit 1215 (WH/LG), harness side and ground.




- Is the resistance greater than 10,000 ohms?

Yes
GO to E10.

No
GO to E9.

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E9 CHECK THE PATS TRANSCEIVER TRANSMIT CIRCUIT 1215 (WH/LG) 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 PCM again.

- Disconnect: PATS Transceiver C2007.
- Measure the resistance between the PCM C175b-22, circuit 1215 (WH/LG), 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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E10 CHECK THE PATS TRANSCEIVER TRANSMIT CIRCUIT 1215 (WH/LG) FOR AN OPEN


- Disconnect: PATS Transceiver C2007.
- Measure the resistance between the PCM C175b-22, circuit 1215 (WH/LG), harness side and the PATS transceiver C2007-3, circuit 1215 (WH/LG), harness side.




- Is the resistance less than 5 ohms?

Yes
GO to E11.

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

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E11 CHECK THE PATS TRANSCEIVER TRANSMIT CIRCUIT 1215 (WH/LG) FOR VOLTAGE


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

- Connect: PATS Transceiver C2007.
- Connect: PCM C175b.
- Ignition ON.
- Enter the following diagnostic mode on the scan tool: PCM DataLogger.
- Trigger the active command TRANSMIT to ON.
- Measure the voltage by backprobing between the PATS transceiver C2007-3, circuit 1215 (WH/LG), 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 E12.

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E12 CHECK THE PATS TRANSCEIVER TRANSMIT CIRCUIT 1215 (WH/LG) FOR A SHORT TO VOLTAGE


- Ignition OFF.
- Disconnect: PCM C175b.
- Disconnect: PATS Transceiver C2007.
- Ignition ON.
- Measure the voltage between the PATS transceiver C2007-3, circuit 1215 (WH/LG), 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 E13.

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E13 CHECK FOR CORRECT PCM OPERATION


- Disconnect all the PCM connectors.
- Check for:
- corrosion
- damaged pins
- pushed-out pins
- Connect all the PCM connectors and make sure they seat correctly.
- Operate the system and verify the concern is still present.
- Is the concern still present?

Yes
INSTALL a new PCM. PROGRAM the PATS keys into the PCM. 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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