The other morning, it was real cold, maybe 13F, and I started the truck after waiting a few seconds. Ever since, the MIL has been on. After troubleshooting the diagnostic code, P2609, that was associated with the MIL, I found no voltage from the ECM to one of the intake heater relays at the relay itself. I tested the battery-to-relay cables/fuse links, relay-to-heater cables, grid heaters, and grounds. Finally found no voltage on the load of one of the relays, then no voltage from ECM to turn the relay on. I have not been able to check the C130 or C2 connectors yet.

Anyone who's a technician/mechanic have any experience with this, or suggestions? I'd hate to have to replace the Cummins computer.

 

I got the code once, replaced the relay.

INTAKE AIR HEATER OPEN
INTAKE AIR HEATER GROUND OPEN
OPEN BATTERY CABLE FROM INTAKE AIR HEATER RELAY
BATTERY CABLE OPEN
#1 INTAKE AIR HEATER RELAY
#2 INTAKE AIR HEATER RELAY
INTERMITTENT CONDITION

1. INTAKE AIR HEATER OPEN
Measure the resistance between the intake air heater supply and ground terminal on each intake air heater.
Is the resistance less than 10 Ohms?
Yes >> Go To 2
No >> Replace the open Intake Air Heater.
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELECTRONIC
CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)
2. INTAKE AIR HEATER GROUND OPEN
Measure the resistance of the intake air heater ground circuit between the intake air heater terminal and the intake
manifold cover ground connection.
NOTE: The intake air heater circuit is grounded through a conductive gasket on the top and bottom of the
air heater (grey colored gaskets).
Is the resistance less than 10 Ohms?
Yes >> Go To 3
No >> Repair the open Intake Air heater ground or replace both heater gaskets with the proper conductive
gaskets..
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELECTRONIC
CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)
3. OPEN BATTERY CABLE FROM INTAKE AIR HEATER RELAY
Measure the resistance of the battery cable between the intake air heater and the intake air heater relay for both
intake air heaters.
Is the resistance less than 10 Ohms?
Yes >> Go To 4
No >> Repair The open or high resistance battery cable from the intake heater relay to heater.
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELECTRONIC
CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)
4. BATTERY CABLE OPEN
Measure the resistance of the battery cable between the battery and the intake air heater relay for both relays.
Is the resistance less than 10 Ohms?
Yes >> Go To 5
No >> Replace the battery cable from the battery to the Intake Air Heater Relay.
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELECTRONIC
CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)
5. #1 INTAKE AIR HEATER RELAY
Disconnect the #1 intake air heater relay signal wire.
Connect a jumper wire from the signal terminal of the #1 intake air heater relay to battery positive.
Did the relay click when 12 volts was applied?
Yes >> Go To 6
No >> Replace #1 Intake Air Heater Relay.
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELECTRONIC
CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)
6. #2 INTAKE AIR HEATER RELAY
Disconnect the #2 intake air heater relay signal wire.
Connect a jumper wire from the signal terminal of the #2 intake air heater relay to battery positive.
Did the relay click when 12 volts was applied?
Yes >> Refer to the INTERMITTENT CONDITION Symptom (Diagnostic Procedure).
No >> Replace #2 Intake Air Heater Relay.
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELECTRONIC
CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)

 

Check the wiring under battery tray right side battery. Remove inner wheel liner to access, I have seen the wires chafing on tray and cause connection problems.

 

Is removing the wheel well as simple as a few screws? I took a peak and I'm not sure the best way to remove it without bending it up.

 

there is what looks like a wire from the battery to the top of relays. this is a 200 amp fuse link. use a test light to see if you have voltage on the post. next take the 16 gage green wire from the ecm that turns on the relays off and jumper from the battery to where it was connected to the relays. now check for voltage on each post of the relay going to the grids. this will defiantly find the problem, you do not need the grid heaters. clear the code and just do not wait to start and no more codes.

 

I'm 53 o4 54 steps ahead of you.

I'm not asking if I need the grid heaters. I am asking for assistance from technicians or mechanics familiar with this.

 

ok if you did the above test and every thing tested ok the problem has to be with the ecm or ait. if the green control wire is broken the ecm monitors current draw to make sure that if it is below 55* and calls for the grid heaters that a load from the solenoids is detected. it will throw a different code if it does not detect it. this tells me that the At detected the need for the heaters and the solenoids was energized. if one solenoid is not making contact it will do this. it is highly unlikely the grid heater itself. the solenoid has copper post's and can get pitted just like a starter solenoid. get a magnetic style alternator- starter amp test gauge that you just hold on the wire, separate the wires between the solenoids and the heaters and remove the green wire and jumper from the battery to the post to activate the solenoids. next hold the amp meter next to each wire, if one has no current check the voltage on that wire if no voltage that solenoid bad. if voltage grid heater bad. if no current on either lead and voltage present you have a bad ground on the grid heater. the grid heater to intake manifold has a special conductive gasket. if some one changed anything and used the upper gasket this can cause this. you can actually Read 12 volts from the grid block to the engine when grid is called for

 

For crying out loud... I'm still 27 steps ahead of you. The relays work. The heaters work. The relay coil grounds are good. The posts are clean. The battery-to-relay wires, including the fusible links, are good. The relay-to-heater wires are good. The heaters' ground is good. The heater has an extra ground jumper, and it's good. The sky is blue. Mary had a little lamb. Humpty Dumpty sat on a wall. Jack and Jill went up the hill. Yada yada yada.


... There is no voltage coming from the ECM to the relay. In order for the heaters to work, the switch has to be turned on, i.e., the ECM has to turn the relay on.

... There is NO voltage coming FROM the ECM TO the relay coil.