Trouble code

[Wilsonic]

I own a 2002 Mack cx 613 and sometimes it's given me da code 6-4 wich says j1939 link when I look it up. Also da 9-2 code comes on & off. Does anybody knows what j1939 link means? Ur replies will be greatly appreciated, thanks.

[turckster]

From Mack Information System:

Blink code 6-4: J1939 serial data line

Failure Mode Identifier FMI: 8 (Abnormal)

Parameter Identification: S231

Message Identification MID: 128 (Abnormal), 142 (Abnormal)

Circuit Description: The V-MAC III system uses the J1939 data line to control communication between the Vehicle Electronic Control Unit (VECU), Engine Electronic Control Unit (EECU), Anti-lock Brake System Control Unit, Allison Transmission Control Unit, and accessory systems, depending on vehicle model and option content. The J1939 data line is an expandable data bus, allowing the addition of accessory control modules (Collision Avoidance, Traction Control, etc.) to be connected to the circuit. The J1939 data line is comprised of two circuits; the L circuit and the H circuit. The two wires are twisted together to prevent outside electrical noise from interfering with the data being carried by the L and H circuits. The V-MAC III system is designed to allow continued engine operation with the loss of the J1939 data line signal as long as the J1587 data line is still operational.

Code Setting Conditions: If either the Vehicle Electronic Control Unit (VECU) or the Engine Electronic Control Unit (EECU) loses communication on the J1939 data line for more than one half second, code 6-4 will set and the Electronic Malfunction Lamp (EML) will turn on. The fault will become inactive if communication resumes for at least on half second. When code 6-4 is active, engine speed will default to 900 RPM. If communication is lost on both the J1587 and J1939 data lines the engine will not run.

Fault code 6-4 will set for some mismatches of VECU and EECU software levels. Blink code 6-4 will also set while the VECU is in the programming mode for Customer Data, Fleet Data, or Mack Data. This code setting condition is normal and the code will become inactive after the ignition key is cycled.

Fault code 6-4 may log, without illuminating the Electronic Malfunction Lamp (EML), on vehicles equipped with Eaton/Bosch ABS/ATC module # 7MN54M2. This nuisance code will not affect the performance of the vehicle. When a vehicle equipped with this ABS/ATC module is being diagnosed for an inactive code 6-4, contact Mack Trucks Service Engineering.

Additional Symptoms: The engine will not start, if communication is lost on both the J1587 and J1939 data lines. If communication is lost on just the J1939 line, the engine will only run at 900 RPM.

Blink code 9-2: Power reset w/o key switch

Failure Mode Identifier (FMI): 4 (Special Instructions)

Parameter Identification (PID): S254

Message Identification (MID): 128/142

Circuit Description: Switched power is supplied to the Vehicle Electronic Control Unit (VECU) through connector J3, pin 17. The VECU ground is provided at connector J3, pin 18. Switched power is supplied to the Engine Electronic Control Unit (EECU) through connector J2, pins 10, 22, and 41. The EECU ground is provided through connector J2, pins 12, 24, and 43.

Code Setting Conditions: The Electronic Malfunction Lamp (EML) will illuminate and code 9-2 will set with MID 142 if the Vehicle Electronic Control Unit (VECU) senses a loss of battery power without the key switch being turned off. The Electronic Malfunction Lamp (EML) will illuminate and code 9-2 will set with MID 128 if the Engine Electronic Control Unit (EECU) senses a loss of switched power without the key switch being turned off. Code 9-2 generally indicates a major vehicle power failure.

If code 9-2 is logged, check the following components for corrosion, loose terminals, and/or poor connections:

• 
  Batteries
  
• 
  Starter Motor
  
• 
  Engine Ground
  
• 
  Ground Circuit Breaker
  
• 
  Left and Right Dashboard Grounds
  
• 
  Power Relays
  
• 
  Engine Electronic Control Unit (EECU) Fuse or Circuit Breaker Connections (MID 128)
  
• 
  Engine Power Distribution Module (EPDM) Connectors (MID 128)
  
• 
  Engine-to-Transmission Transition Connector (MID 128)
  
• 
  Vehicle Electronic Control Unit (VECU) Fuse or Circuit Breaker Connections (MID 142)
  

Clean, repair or replace as necessary.

To clear code 9-2, turn the key switch ON, turn the key switch OFF for 6 seconds, then turn the key switch back ON. The code will clear in several seconds.

The 9-2 code may be your problem, momentary loss of power would cause loss of communication with one ecu. Make sure battery connections are good and clean, same with all grounds, starter connections. Check the battery condition as well, one bad battery can be a problem. Good luck.

[Victor520]

this is the code table : code table, hope it can help you