GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 1998 🢒 Venture Ext. 🢒 Engine 🢒 Engine Controls - 3.4L 🢒 Data Link Connector Diagnosis

Object Number: 259361 Size: LF
Engine Controls Components
Power, Ground, MIL, DLC
OBD II Symbol Description Notice
Handling ESD Sensitive Parts Notice

Circuit Description

The Class II serial data circuit to the DLC allows bi-directional communication between the PCM and the scan tool.

Diagnostic Aids

Check the following items:

    •  For the PCM to establish communication with the scan tool, system voltage must be between 9.0 and 16.0 volts. If system voltage is not within this range, refer to Charging System Check in Engine Electrical.
    •  Ensure that the correct application (model year, carline, VIN code) has been selected on the scan tool, if communication still cannot be established try the scan tool on another vehicle to ensure that the scan tool, Vehicle Interface Module, or cables are not the cause of the condition.
    •  An intermittent may be caused by a poor connection, rubbed through wire insulation or a wire broken inside the insulation. Check for poor connections or a damaged harness. Inspect the PCM harness and connectors for improper mating, broken locks, improperly formed or damaged terminals, poor terminal to wire connection, and damaged harness.

Test Description

The numbers below refer to the Step numbers on the diagnostic table:

  1. This vehicle is equipped with a PCM which utilizes an electrically erasable programmable read only memory (EEPROM). When the PCM is being replaced, the new PCM must be programmed. Refer to Powertrain Control Module Replacement/Programming .

Data Link Connector Diagnosis

Step

Action

Value(s)

Yes

No

1

Did you perform the Powertrain OBD System Check?

--

Go to Step 2

Go to the Powertrain On Board Diagnostic (OBD) System Check

2
  1. Turn on the ignition switch, leaving the engine off.
  2. Connect a test light between the data link connector (DLC) battery feed and ground.

Is the test lamp on?

--

Go to Step 4

Go to Step 3

3

Use the test lamp in order to probe between the DLC battery feed circuit and ground.

Is the test lamp on?

--

Go to Step 9

Go to Step 10

4
  1. Turn on the ignition switch, leaving the engine off.
  2. Use a digital multimeter (DMM) in order to probe the Class II serial data circuit between the DLC and ground.

Does the voltage equal the specified value?

0 V

Go to Step 5

Go to Step 7

5
  1. Turn off the ignition switch.
  2. Disconnect the powertrain control module (PCM).
  3. Turn on the ignition switch, leaving the engine off.
  4. Use the DMM in order to probe the Class 2 serial data circuit between the DLC and B+.

Does the voltage equal the specified value?

0 V

Go to Step 6

Go to Step 8

6
  1. Test the Class II serial data circuit for an open between the DLC and the PCM.
  2. Repair the circuit as necessary. Refer to Wiring Repairs in Wiring Systems.

Is the circuit OK?

--

Go to Step 11

--

7
  1. Test the Class II serial data circuit for a short to voltage.
  2. Repair the circuit as necessary. Refer to Wiring Repairs in Wiring Systems.

Is the circuit OK?

--

Go to Step 11

--

8

Locate and repair a short to ground in the Class II serial data circuit. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

--

Go to Powertrain On Board Diagnostic (OBD) System Check

--

9

Locate and repair an open in the DLC ground circuit. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

--

Go to Powertrain On Board Diagnostic (OBD) System Check

--

10

Locate and repair an open or a short to ground in the DLC battery feed circuit. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

--

Go to Powertrain On Board Diagnostic (OBD) System Check

--

11

Important: : A replacement PCM must be programmed. Refer to Powertrain Control Module Replacement/Programming .

Replace the PCM.

Did you complete the repair?

--

Go to Powertrain On Board Diagnostic (OBD) System Check

--