GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Buick 🢒 1996 🢒 Regal 🢒 Engine 🢒 Engine Controls - 3.8L 🢒 Data Link Connector Diagnosis

Refer to

Engine Grounds, Serial Data, MIL Control


Object Number: 23173 Size: FS
Engine Controls Components
Data Link Connector Diagnosis
Ignition Control Module
OBD II Symbol Description Notice
Handling ESD Sensitive Parts Notice
Handling ESD Sensitive Parts Notice
 .

Circuit Description

The Class 2 serial data circuit to the DLC allows bi-directional communication between the PCM and the scan tool. If communication between the scan tool and the PCM cannot be established, the procedure in the DLC Diagnosis table should be used to diagnose the condition.

Diagnostic Aids

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

Number(s) below refer to the Step number(s) 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.

DLC Diagnosis

Step

Action

Value(s)

Yes

No

1

Was the Powertrain On-Board Diagnostic (OBD) System Check performed?

--

Go to Step 2

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

2
  1. Disconnect the scan tool.
  2. Turn ON the ignition switch.
  3. Connect a J 35616-200 test light between the DLC battery feed and ground circuits.

Is the test light ON?

--

Go to Step 4

Go to Step 3

3

Probe the DLC battery feed circuit with a test light to chassis ground.

Is the test light ON?

--

Go to Step 9

Go to Step 10

4

Probe the Class 2 serial data circuit at the DLC with a J 39200 Digital Multimeter to ground.

Is the voltage near the specified value?

0V

Go to Step 5

Go to Step 7

5
  1. Turn OFF the ignition switch.
  2. Disconnect the PCM.
  3. Turn ON the ignition switch.
  4. Probe the Class 2 serial data circuit at the DLC with a J 39200 Digital Multimeter to B+.

Does the voltage measure the specified value?

0V

Go to Step 6

Go to Step 8

6
  1. Check the Class 2 serial data circuit for an open between the DLC and the PCM.
  2. If a problem is found, repair as necessary. Refer to Repair procedures in Electrical Diagnosis.

Was a problem found?

--

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

Go to Step11

7
  1. Check the Class 2 serial data circuit for a short to voltage.
  2. If a problem is found, repair as necessary. Refer to Repair procedures in Electrical Diagnosis.

Was a problem found?

--

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

Go to Step11

8

Locate and repair the short to ground in the Class 2 serial data circuit. Refer to Repair procedures in Electrical Diagnosis.

Is action complete?

--

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

--

9

Locate and repair the open in the DLC ground circuit. Refer to Repair procedures in Electrical Diagnosis.

Is action complete?

--

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

--

10

Locate and repair the open or short to ground in the DLC battery feed circuit. Refer to Repair procedures in Electrical Diagnosis.

Is action complete?

--

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

--

11

Replace the PCM.

Important:: Replacement PCM must be programmed. Go to Powertrain Control Module Replacement/Programming .

Is action complete?

--

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

--