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Experience:  GM Grand Master Technician 2007. 14 years experience.
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My 04 silverado duramax blew the edm fuse. replaced now only

Customer Question

My 04 silverado duramax blew the edm fuse. replaced now only running of 4 cylinders. throwing codes p1226, 1229, 1235, 1244. also a u1800. Is the ficm bad?
JA: Do all the fuses have the correct amperage for the circuits they're in?
Customer: yes
JA: Are you fixing your Silverado yourself? What have you tried so far?
Customer: yes, tried checking some of the injector harness for any chaffed wires. both power wires to the ficm have power. I have yet to load test the injector harness. I did notice a faint odor like electronics burning near the ficm.
JA: Anything else you want the mechanic to know before I connect you?
Customer: will the ficm usually reset after a key cycle?
Submitted: 10 months ago.
Category: Chevy
Expert:  david craig replied 10 months ago.

Hi Im David.......

#PIP3394E: Duramax Diesel Injector Driver Codes - keywords ECM FICM P0300 P1223 P1226 P1229 P1232 P1235 P1238 P1241 P1244 chafe circuit chuggle connector miss misfire surge wire - (Feb 1, 2008)

Subject:Duramax Diesel Injector Driver Codes

Models:2004-2005 Chevrolet Kodiak, Silverado

2004-2005 GMC Sierra, Topkick

with 6.6 Engine (VIN 2 - RPO LLY)

This PI was superceded to include GMT560 trucks. Please discard PIP3394D.

The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.


Misfire, rough running, surge, chuggle, and possible MIL/SES light on.


Do not replace fuel injectors for trouble codes P1223, P1226, P1229, P1232, P1235, P1238, P1241 or P1244. When these codes are set, there is either a wiring concern between the Engine Control Module (ECM) and the Fuel Injection Control module (FICM), or a concern with the control module itself, (ECM/FICM). If there is a concern on the injector driver circuits (open, short to ground or high resistance), it is possible to have a high injector balance rate.

  1. Diagnose all injector driver codes using the current SI diagnostics.
  2. If all SI diagnostics are inconclusive, inspect for wire chafes at the Fuel Injector Control Module (FICM) wiring harness brace. The wiring harness brace is located 4 to 6 inches away from the FICM connectors. The wiring harness is nylon tied to the wiring harness brace. It may be necessary to remove the nylon tie to inspect the harness. Repair any wire chafes following SI wire repair procedures. Insulate the harness with wiring conduit or a suitable material so the wires will not chafe again.
  3. Also inspect the C107 connector for wire chafes. The C107 connector is found above the left (driver side) rocker cover. The wiring harness may relax and lay on top of the C107 support brace. This support brace is located right below the C107 connector. Repair any wire chafes following SI wire repair procedures. Insulate the harness with wiring conduit or a suitable material so the wires will not chafe again.
Customer: replied 10 months ago.
My truck is an 04 LB7.
Expert:  david craig replied 10 months ago.

#04-06-04-001C: LB7/LBZ/LLY/LMM - Intermittent Driveability Conditions-No Crank, Crank No Start, Hard to Start, MIL/SES, HEsitation, Lack of Power, Surge, Misfire, Fuel Knock, IPC Indicates No Oil Pressure, DTCs Set - (Nov 28, 2006)

Subject:LB7 LBZ LLY LMM -- Intermittent Driveability Conditions Such as No Crank, Crank But No Start, Hard to Start, MIL/SES, Hesitation, Lack of Power, Surge, Misfire, Fuel Knock, No Serial Data Communication, IPC Indicates No Oil Pressure, DTCs Set (Inspect Connection/Replace Connector Bodies)

Models:2001-2007 Chevrolet Silverado Pickups

2006-2007 Chevrolet Express Vans

2003-2007 Chevrolet Kodiak C4500/C5500 Series

2001-2007 GMC Sierra Pickups

2006-2007 GMC Savana Vans

2003-2007 GMC TopKick C4500/C5500 Series

with 6.6L DuramaxTM Diesel Engine (VINs 1, 2, 6, D -- RPOs LB7, LLY, LMM, LBZ)

This bulletin is being revised to update the model years and add Condition and Correction content. Please discard Corporate Bulletin Number 04-06-04-001B (Section 06 -- Engine/Propulsion System).


Some customers may comment on any of the following various intermittent driveability conditions:

•No crank

•Crank but no start

•Hard to start

•MIL/SES Illuminated with EGR DTCs, cam sensor DTCs, fuel pressure DTCs, turbocharger DTCs, injection circuit DTCs


•Lack of power



•Fuel knock

•No serial data communication

•IPC indicates no oil pressure

Various engine faults or DTCs may occur due to backed out pins in the following main engine harness connectors:

C107 and C118 (38-way) Engine Harness to the Engine Chassis Harness Connector

C108 and C119 (24-way) Engine Harness to the Engine Chassis Harness Connector


The main engine to chassis connectors utilize a plastic tab formed into the connector body as a terminal lock (5). If a terminal lock (5) is damaged or broken, the terminal (1, 4) will be pushed partially out of the connector body (2, 3) during assembly and will make poor or no contact with its mating terminal. Various and intermittent engine control faults may occur.


Notice: When reconnecting the engine to chassis connectors, slide the Primary Lock Reinforcement partially out of the male side connectors to support the ends of the male pins upon installation. Guide the chassis side connectors straight into the engine connectors when using the lever lock to avoid terminal misalignment. Failure to do so may cause terminal lock breakage.

Inspect the terminals in the male and female sides of the connectors for broken terminal locks by removing the terminal position assurance (TPA) comb at the back of the connector (if equipped) and gently pushing and pulling on the wire in question. If the wire moves within the connector and does not lock into position, the connector body should be replaced.

Connector Location

The following connectors are all located at the engine harness to engine chassis harness that is mounted to the top of the driver side valve cover.

C107 and C118 (38-way) Engine Harness to the Engine Chassis Harness Connector

C108 and C119 (24-way) Engine Harness to the Engine Chassis Harness Connector

If an illustration is needed to locate the connector in question, please refer to SI and build your vehicle publication to view. Then select the following areas:

  1. Body
  2. Wiring Systems
  3. Component Location
  4. Master Electrical Component List

Connector Components

Terminal Position Assurance (TPA) (C107 and C118 only)

Cable Seal

Female Terminal

Lever Lock

  1. Connector Body - Female
  2. Connector Seal
  3. Primary Lock Reinforcement (PLR) - Female (C108 and C119 24-way connectors only)
  4. Primary Lock Reinforcement (PLR) - Male (C108 and C119 24-way connectors only)
  5. Connector Body - Male
  6. Male Terminal
  7. Cable Seal
  8. Terminal Position Assurance (TPA) (If equipped)

The 6.6L diesel engine utilizes a 24-way and a 38-way Packard Lever Lock GT Series sealed connector for the engine to chassis connection. Connector components can be serviced using the J 38125 Terminal Kit. Connector bodies are available through GMSPO. The following components are available from the J 38125 Terminal Kit:

Important: If the correct terminals are not found, verify that the tray numbers have been updated.

Parts Information

Part Number



Connector Body, 24-way female(C108 and C119)


Connector Body, 24-way male (C108 and C119)


Connector Body, 38-way female(C107 and C118)


Connector Body, 38-way male(C107 and C118)

Expert:  david craig replied 10 months ago.

do you still need assistance?

Customer: replied 10 months ago.
Sorry David for delay. Update, I replaced the FICM.(opened up the old one and found capacitors burned) started it up but still ran on 4 cylinders. checked codes and got the 202, 203, 205, 208 codes. I tried to ohm the FICM connector but get 0L on my meter. ohm the injector harness at valve cover and getting .3-.4 on passenger and rear driver. I have yet to test the front driver harness at valve cover. could the harness at the FICM be the problem?