How do I fix a serial 2 data link malfunction on a 4 cylinder 99 sunfire

Electric in tank fuel pump is defective or the relay or wiring for the pump is faulty.

Did you check for BCM codes
DTC B1477
Retained Accessory Power Circuit Low
DTC B1478
Retained Accessory Power Circuit High
DTC B1397
Device Voltage Reference Out #1 CKT Low
DTC B1398
Device Voltage Reference Out #1 CKT High
Charging system check ?

Diagnostic System Check - Retained Accessory Power
Test Description
The numbers below refer to the step numbers on the diagnostic table.

1. Lack of communication may be due to a partial malfunction of the class 2 serial data circuit or due to a total malfunction of the class 2 serial data circuit. The specified procedure will determine the particular condition.


2. This step is checking for DTCs in the BCM.


3. This step is checking for RAP specific DTCs.

Step

Action

Yes

No

1

Install a scan tool.

Does the scan tool power up?
Go to Step 2
Go to Scan Tool Does Not Power Up in Data Link Communications

2

1. Turn ON the ignition, with the engine OFF.
2. Attempt to establish communication with the body control module.

Does the scan tool communicate with the BCM?
Go to Step 3
Go to Scan Tool Does Not Communicate with Class 2 Device in Data Link Communications

3

Important: The engine may start during the following step. Turn OFF the engine as soon as you have observed the Crank power mode.

1. Access the Class 2 Power Mode in the Diagnostic Circuit Check on the scan tool.
2. Rotate the ignition switch through all positions while observing the Class 2 Power Mode on the Scan Tool. Refer to the Serial Data Power Mode table within the Body Control System Description and Operation in Body Control Systems, for a list of the power mode states that correspond to each ignition switch position.

Does the Class 2 Power Mode parameter reading match the ignition switch position for all the selected positions?
Go to Step 4
Go to Power Mode Mismatch in Body Control System

4

Select the BCM display DTCs function on the scan tool.

Does the scan tool display any DTCs?
Go to Step 5
Go to the Symptoms list in the appropriate service category

5

Does the scan tool display B1477 or B1478?
Go to Diagnostic Trouble Code (DTC) List
Go to Symptoms - Retained Accessory Power

Is check engine light Lit ? You should have all the computers on the vehicle check for DTC'S - diagnostic trouble codes ! Check the battery an all connections !
Diagnostic Starting Point - Engine Electrical
Begin the system diagnosis with the Diagnostic System Check - Engine Electrical . The Diagnostic System Check will provide the following information:
?€¢
The identification of the control module(s) which command the system.

?€¢
The ability of the control modules to communicate through the serial data circuit.

?€¢
The identification of any stored diagnostic trouble codes (DTCs) and their status.

The use of the Diagnostic System Check will identify the correct procedure for diagnosing the system and where the procedure is located.
Diagnostic System Check - Engine Electrical
Test Description
The numbers below refer to the step numbers on the diagnostic table.
Lack of communication may be due to a partial malfunction of the class 2 serial data circuit or due to a total malfunction of the class 2 serial data circuit. The specified procedure will determine the particular condition.
The symptom list in Symptoms will determine the correct diagnostic procedure to use.
The presence of DTCs which begin with "U" indicate some other module is not communicating. The specified procedure will compile all the available information before tests are performed.
Step
Action
Yes
No

1
Did you perform the Battery Inspection/Test?
Go to Step 2
Go to Battery Inspection/Test

2
Install a scan tool.
Does the scan tool power up?
Go to Step 4
Go to Scan Tool Does Not Power Up in Data Link Communications

3
Important: The engine may start during the following step. Turn OFF the engine as soon as you have observed the Crank power mode.
Access the Class 2 Power Mode in the Diagnostic Circuit Check on the scan tool.
Rotate the ignition switch through all positions while observing the Class 2 Power Mode on the Scan Tool. Refer to the Serial Data Power Mode table within the Body Control System Description and Operation in Body Control System for a list of the power mode states that correspond to each ignition switch position.
Does the Class 2 Power Mode parameter reading match the ignition switch position for all the selected positions?
Go to Step 4
Go to Power Mode Mismatch in Body Control System

4
Turn ON the ignition, with the engine OFF.
Attempt to communicate with each module on the class 2 serial data circuit:
• The body control module (BCM)
• The driver information center (DIC)
• The instrument panel cluster (IPC)
• The powertrain control module (PCM)
Does the scan tool communicate with any module on the class 2 serial data circuit?
Go to Step 5
Go to Scan Tool Does Not Communicate with Class 2 Device in Data Link Communications

5
Select the Display DTCs function for each module. If using a Tech 2, use the Class 2 DTC Check feature in order to determine which modules have DTCs set.
Record all of the displayed DTCs the DTC status and the module which set the DTC.
Does the scan tool display any DTCs?
Go to Step 6
Go to Symptoms - Engine Electrical

6
Does the scan tool display any DTC beginning with "U"?
Go to Diagnostic Trouble Code (DTC) List in Data Link Communications
Go to Step 7

7
Does the scan tool display any DTC beginning with "B"?
Go to Diagnostic Trouble Code (DTC) List in Body Control Systems
Go to Diagnostic Trouble Code (DTC)

The IPC calculates the mileage based on the vehicle speed signal circuit from the powertrain control module (PCM). The odometer will display ERROR if an internal IPC memory malfunction is detected or there is a class 2 communication fault. The odometer displays either miles or kilometers as requested by the activation of the English/metric button on the driver information center (DIC). The associated indicator (km or MI) illuminates.
You probably have A class 2 serial data communication malfunction. All the Modules on your vehicle talk, share information on the data network an if something brings it down ,shorts it out, the vehicle will not start .
The data link connector (DLC) allows a scan tool to communicate with the class 2 serial data line. The DLC is a standardized 16 way connector located below the instrument panel and close to the steering column. Both the connector design and location are dictated by industry wide agreements. All DLCs are required to provide a power supply, hot at all times, to terminal 16. This circuit is used to power the scan tool. All DLCs supply a power ground at terminal 4 and a signal ground at terminal 5. The class 2 serial data circuit is provided at terminal 2 of the DLC.
You probably need to take this to a ASE certified repair shop or the a GM dealership ! Because if you are asking here you probably don't know about this stuff, an you sure don't have a factory scan tool to see which modules have DTC'S - diagnostic trouble codes stored .
You

What pins did your friend jump in the DLC ,2 an 4 ? they don't call it ALDL any more ! Does the vehicle start an run ?
The data link connector (DLC) is a standardized 16 cavity connector. Connector design and location is dictated by an industry wide standard, and is required to provide the following:
?€¢
Scan tool power battery positive voltage at terminal 16.

?€¢
Scan tool power ground at terminal 4.

?€¢
Common signal ground at terminal 5.

?€¢
Class 2 signal at terminal 2.

I wonder how many friends out there mess up other friends vehicles from stuff they see on the internet . When are you people going to learn , your messing with complex electronics !!!!! He shorted out the class 2 serial data communication network !
Do you know what this is ? if not you need to take to your local GM Mr. goodwrench !
Class 2 Serial Data Link
The data link is configured as a ring with discrete lines entering and leaving each module. This allows communications to the modules on the ring if one of the two discrete circuits is open.
A total list of the control modules on the Class 2 Serial Data Line can include the following:
?€¢
Dash Integration Module (DIM)

?€¢
Driver Door Module (DDM)

?€¢
Electronic Brake Control Module (EBCM)

?€¢
Head Up Display (HUD) w/UV6

?€¢
HVAC Control Module w/C67

?€¢
Inflatable Restraint Sensing and Diagnostic Module (SDM)

?€¢
Instrument Panel Cluster (IPC)

?€¢
Instrument Panel Integration Module (IPM) w/CJ2

?€¢
Memory Seat Module (MSM) w/A45

?€¢
Powertrain Control Module (PCM)

?€¢
Radio

?€¢
Rear Integration Module (RIM)

?€¢
Remote Control Door Lock Receiver (RCDLR)

?€¢
Remote Playback Device - CD Changer w/U1S

?€¢
Theft Deterrent Control Module

?€¢
Vehicle Interface Unit (VIU) w/UE1

Power door serial data does not communicate with the scan tool via the DLC. Power door serial data information is interpreted by the driver door module (DDM) and transmitted on the Class 2 data link by the DDM.
Power door serial data is used for serial data communication between the four door modules as well as the driver door switch assembly (DDSA
Scan Tool Does Not Communicate with Class 2 Device
Modules connected to the class 2 serial data circuit monitor for serial data communications during normal vehicle operation. Operating information and commands are exchanged among the modules. Connecting a scan tool to the DLC allows communication with the modules for diagnostic purposes.
The engine will not start when there is a total malfunction of the class 2 serial data circuit while the engine is not running.
Test Description
The numbers below refer to the step numbers on the diagnostic table.

1. A partial malfunction in the class 2 serial data circuit uses a different procedure from a total malfunction of the class 2 serial data circuit.


2. The DTC U1300, U1301, and U1305 may be retrieved with a history status. These DTCs are not the cause of the present condition.


3. A State of Health DTC with a history status may be present along with a U1000 or a U1255 with a current status. This indicates that the malfunction occurred when the ignition was on.

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its triggered buy ignition lock cylinder if its worn it malfunctions replace ignition cylinder

The protocol is class 2 . Maybe your code reader is no good .
012 GM Class II Communications

Data Link Connector (DLC)
The data link connector (DLC) contains the following serial data links:
• Class II
• Entertainment and Comfort (E&C)
The DLC also provides a power source for the scan tool as follows:
• Unswitched voltage (B+) at DLC terminal 16 (circuit 1450)
• Ground at terminal 4 (circuit 1450) and terminal 5 (circuit 1550)

Class II Serial Data Link
The class II serial data link allows the following modules to communicate data with each other:
• Body control module (BCM)
• Electronic brake traction control module (EBTCM)
• Heater-A/C control (if equipped with RPO CJ2)
• Instrument panel cluster (IPC)
• Powertrain control module (PCM)
• Inflatable Restraint Sensing and Diagnostic Module (SDM).
The Class II serial data link allows a Scan Tool scan tool to communicate with the above modules for diagnostic and testing purposes. The Class II serial data link is located at the DLC connector terminal 2. Terminal 2 consists of the following circuits:
• Circuit 1036
• Circuit 1037
• Circuit 1128
• Circuit 1049
• Circuit 1122
• Circuit 1132
Entertainment and Comfort (E&C) Serial Data Link
The entertainment and comfort (E&C) serial data link allows a scan tool to communicate with the radio or the mobile telephone handset the remote CD player (if equipped). This communication is for diagnostic and testing purposes. The E&C serial data link is located at the DLC connector terminal 14, circuit 835.
PIN #9 goes to the air bag module .

One coil serves those two cylinders (no. 1 and 4), so try repllacing that coil.

Given that most of the trouble codes are for the O2 sensor, I think I would change it. The multiple misfires could be because of improper fuel/air mixture caused by a bad sensor. Disconnect the negative(-) battery terminal then change the sensor. Disconnecting the negative(-) should reset the computer and allow the fuel/air mixture to return to default allowing the engine to start.
P0130 - O2 Sensor Circuit Malfunction (Bank 1 Sensor 1)
P0134 - O2 Sensor Circuit No Activity Detected (Bank 1 Sensor 1)
P0135 - O2 Sensor Heater Circuit Malfunction (Bank 1 Sensor 1)
P0141 - O2 Sensor Heater Circuit Malfunction (Bank 1 Sensor 2)
P0300 - Random/Multiple Cylinder Misfire Detected