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Chris
Chris, Auto Service Technician
Category: Car
Satisfied Customers: 13467
Experience:  43 years of automotive repair, Smog license
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2003 3500 diesel..Runs great cold as soon as it gets to operating

Customer Question

2003 3500 diesel..Runs great cold as soon as it gets to operating temp, the engine has a REAL bad stumble at 1200 rpm. Only code is P1652
Submitted: 4 years ago.
Category: Car
Expert:  Chris replied 4 years ago.
Hello and thank-you for letting me help you with your problem. Can you drive past the stumble , and will it run ok above 1200 rpm?

Chris
Customer: replied 4 years ago.
Yes....once you get past the stumble it runs fine. When the engine is cold there is no stumble at all. Only once engine gets to oper. temp. It does this every time
Expert:  Chris replied 4 years ago.
Ok, I am leaning towards a problem with the APPS. I want to check some things first and will do that when I get to my shop in about an hour. I will get back to you ASAP with an answer.

Chris
Expert:  Chris replied 4 years ago.

Ok, you may have a short in the engine harness, or a failing ECM. Have the code cleared, and then drive it, let it stumble, and recheck the code. Let me know if the P1652 returns.

Let me know,

Chris

Symptom:
P1652-J1850 SHORT TO GROUND
When Monitored and Set Condition:
P1652-J1850 SHORT TO GROUND
When Monitored: While the ignition is on.
Set Condition: The ECM detects a short to ground on the J1850.
POSSIBLE CAUSES
ECM
J1850 SHORTED
COMMUNICATION
TEST ACTION APPLICABILITY
1 Turn the ignition off.
Disconnect the ECM harness connectors.
NOTE: Check connectors - Clean/repair as necessary.
Measure the resistance between the J1850 circuit in the ECM harness connector and
battery negative.
Is the resistance less than 10 Ohms?
ENGINE- 5.9L
CUMMINS 24V
DIESEL
Yes ! Go To 2
No ! Replace the ECM.
2 Measure the resistance between the J1850 circuit and all other circuits in both ECM
connectors.
Is the resistance greater than 100k ohms?
ENGINE- 5.9L
CUMMINS 24V
DIESEL
Yes ! Refer to the Body Diagnostic book Communications section.
No ! Repair J1850 shorted to another circuit.