DTC P1604 Lost Communications with Driver Information and Displays Control (IPC) System. Buick Park Avenue 1998

For 1990-2009 cars only

Makes 🢒 Buick 🢒 1998 🢒 Park Avenue 🢒 DTC 🢒 DTC P1604 Lost Communications with Driver Information and Displays Control (IPC) System

Refer to

Cell 20: Engine Controls -- PCM MIL and Data Link Connector (DLC)

Circuit Description

The PCM uses the class 2 serial data circuit to communicate with various other devices and systems in the vehicle. The PCM ensures that communication remains established by monitoring the class 2 serial data circuit for state of health messages from the other devices using the circuit. If the PCM detects a loss of the state of health serial data message from the IPC, DTC P1604 will be set.

Conditions for Running the DTC

•	The ignition is ON.

•	System voltage is greater than 8.2 volts.

Conditions for Setting the DTC

•	The PCM detects a loss of serial data from the IPC.

•	The above condition is present for longer than 5 seconds.

Action Taken When the DTC Sets

•	The PCM will not illuminate the Malfunction Indicator Lamp (MIL).

•	The PCM will store conditions which were present when the DTC set as Fail Records data only. This information will not be stored as Freeze Frame data.

Conditions for Clearing the MIL/DTC

•	A history DTC will clear after 40 consecutive warm-up cycles have occurred without a malfunction.

•	The DTC can be cleared by using the scan tool Clear Info function or by disconnecting the PCM battery feed.

Diagnostic Aids

An intermittent may be caused by a poor connection, rubbed through wire insulation or a wire broken inside the insulation. Check for the following conditions:

•

Intermittent short circuit on the serial data circuit. Refer to

Cell 20: Engine Controls -- PCM MIL and Data Link Connector (DLC)

•	Poor connection.

Inspect the PCM and the affected control module harness and related connectors for improper mating, broken locks, improperly formed or damaged terminals, and poor terminal to wire connection.

•	Damaged harness.

Inspect the wiring harness for damage. Check for an intermittent short or open circuit in the wiring harnesses related to the affected control module, including the ignition positive voltage, battery positive voltage, ground, and serial data circuits. Refer to Wiring Repairs .

Reviewing the Fail Records vehicle mileage since the diagnostic test last failed may help determine how often the condition that caused the DTC to be set occurs. This may assist in diagnosing the condition.

DTC P1604 - IPC Serial Data Circuit

Step	Action	Values	Yes	No
1	Was the Powertrain On-Board Diagnostic System Check performed?	--	Go to Step 2	Go to Powertrain On Board Diagnostic (OBD) System Check
2	Important: If a loss of DLC data has already been diagnosed using the DLC Diagnosis table, clear this DTC and continue diagnosis with the Powertrain On Board Diagnostic (OBD) System Check Attempt to select IPC data with the scan tool. Can IPC data be displayed?	--	Go to Step 3	Go to Step 4
3	Turn OFF the ignition switch. Disconnect the PCM and the IPC. Check the class 2 serial data circuit for an open between the IPC and the PCM. If a problem is found, repair as necessary. Refer to Wiring Repairs . Was a problem found?	--	Go to Step 6	Go to Diagnostic Aids
4	Check the class 2 serial data circuit for a poor connection at the IPC. If a problem is found, repair as necessary. Refer to Wiring Repairs . Was a problem found?	--	Go to Step 6	Go to Step 5
5	Check the class 2 serial data circuit for a poor connection at the PCM. If a problem is found, repair as necessary. Refer to Wiring Repairs . Was a problem found?	--	Go to Step 6	Go to Diagnostic System Check - Data Link Communications
6	Review and record scan tool Fail Records data. Clear DTCs. Operate the vehicle within Fail Records conditions. Using a scan tool, monitor Specific DTC info for DTC P1604. Does the scan tool indicate DTC P1604 failed?	--	Go to Step 2	System OK