Has anyone experience a fluctuating idle during cold temperatures? This morning when starting, it was around 30 degrees after starting, it seemed like it was hunting. About every second it would increase about 50 rpm and then back to normal. It did this until I pressed on the accelerator and increased the idle up to about 1500 rpm then back. It then smoothed out.

Anyway just wondering...

 

No problems with cold idle here. The only thing about cold idle with my Cummins is that it sounds like the older Cummins without the pilot injection until the temp gets to around 150 degs.

 

yes I have... I think you will find it happens at the exact same time the grid heaters cycle. I turned one of the overhead lights on and watched...
light dims..., rpm dipps and returns to 1000
light goes bright..., rpm jumps above 1000 and then returns to 1000
repeat...

at least this is the way it is happening on my truck.

 

I'll check in the moring. We are supposed to have a hard freeze. I'll turn on the overhead lamp and see if the timing is in sync with the heating grid.

Thanks for the info.

silverramer

"If the Lord wanted snow in Texas, he would have made BS white."

 

Hey, i'll be joining you with that hard freeze (Ft Hood) . Yes, have had the same issue...go ahead a bring the rpm's up alittle bit and it should clear. Yes, sounds like its hunting for fuel...never caused any problems for me. I'm plugging in my block heater this eve...

 

The intermittent idle has yet to happen again. However, if I check codes by reading the dash, the following code appears:

“C-code
23 67”

Does anyone know what this means? Maybe it had something to do with the strange idle I had. The check engine light is not set.

Any insight would be appreciated.

 

copy and pase from another thread...

Here is the complete list of diagnostic trouble codes for the 2003 Cummins. Do not try and use them for gas engines, as they may not be the same.

P0016 Crankshaft/Camshaft Timing Misalignment/Out-of-Sync
P0071 Ambient Temperature Sensor Performance / Rationality
P0072 Ambient Temperature Sensor Low
P0073 Ambient Temperature Sensor High
P0088 Fuel Rail Pressure Too High
P0106 Manifold Absolute Pressure Sensor Performance / Rationality
P0107 Manifold Absolute Pressure Sensor Low
P0108 Manifold Absolute Pressure Sensor High
P0111 Intake Air / Charge Temperature Sensor Performance / Rationality
P0112 Intake Air / Charge Temperature Sensor Low
P0113 Intake Air / Charge Temperature Sensor High
P0116 Engine Coolant Temperature Sensor Performance / Rationality
P0117 Engine Coolant Temperature Sensor Low
P0118 Engine Coolant Temperature Sensor High
P0128 Cooling System Error / Thermostat Rationality
P0148 Fuel Delivery Error
P0169 Water-in-Fuel Detected For Too Long
P0192 Fuel Rail Pressure Sensor Low
P0193 Fuel Rail Pressure Sensor High
P0201 Fuel Injector 1 Circuit
P0202 Fuel Injector 2 Circuit
P0203 Fuel Injector 3 Circuit
P0204 Fuel Injector 4 Circuit
P0205 Fuel Injector 5 Circuit
P0206 Fuel Injector 6 Circuit
P0217 Coolant Temperature Too High
P0219 Engine Overspeed
P0234 Turbocharger Overboost Condition
P0236 Turbocharger Boost Pressure Sensor Performance / Rationality
P0237 Turbocharger Boost Pressure Sensor Low
P0238 Turbocharger Boost Pressure Sensor High
P0251 Injection Pump Fuel Valve Feedback
P0300 Multiple Cylinder Misfire
P0301 Cylinder 1 Misfire
P0302 Cylinder 2 Misfire
P0303 Cylinder 3 Misfire
P0304 Cylinder 4 Misfire
P0305 Cylinder 5 Misfire
P0306 Cylinder 6 Misfire
P0335 Crankshaft Position Sensor Circuit
P0336 Crankshaft Position Sensor Performance
P0337 Crankshaft Position Sensor Circuit Low
P0338 Crankshaft Position Sensor Circuit High
P0340 Camshaft Position Sensor Circuit
P0341 Camshaft Position Sensor Performance / Rationality
P0381 Wait-to-Start Lamp Inoperative
P0461 Fuel Level Sensor 1 Performance / Rationality
P0462 Fuel Level Sensor 1 Low
P0463 Fuel Level Sensor 1 High
P0477 Exhaust Pressure Control Relay Low
P0478 Exhaust Pressure Control Relay High
P0480 Cooling Fan 1 Control Circuit/Open (Low Speed Fan Relay)
P0483 Cooling Fan Speed
P0500 Vehicle Speed Sensor 1 Circuit, or No Vehicle Speed Reference Signal 1
P0514 Battery Temperature Sensor Performance / Rationality
P0516 Battery Temperature Sensor Low
P0517 Battery Temperature Sensor High
P0521 Oil Pressure Sensor Performance / Rationality
P0524 Oil Pressure Too Low
P0532 A/C Pressure Sensor Low
P0533 A/C Pressure Sensor High
P0541 Intake Air Heater Relay 1 Low
P0542 Intake Air Heater Relay 1 High
P0562 Battery Voltage Low
P0563 Battery Voltage High
P0572 Brake Switch 1 Low
P0573 Brake Switch 1 High
P0580 Speed Control Multiplexed Switch 1 Low
P0581 Speed Control Multiplexed Switch 1 High
P0602 Control Module Programming Error/NotProgrammed
P0604 Internal Control Module RAM Integrity Failure
P0606 Internal ECM Processor
P0607 ECU Internal Performance
P0622 Generator Field Control Circuit
P0628 Fuel Pump Relay Circuit Low, or Fuel Lift Pump Control Circuit Low
P0629 Fuel Pump Relay Circuit High, or Fuel Lift Pump Control Circuit High
P0630 VIN Not Programmed in PCM
P0633 SKIM Key Not Programmed in PCM
P0642 Sensor Reference Voltage 1 Circuit Low
P0643 Sensor Reference Voltage 1 Circuit High
P0646 A/C Clutch Relay Circuit Low
P0647 A/C Clutch Relay Circuit High
P0652 Sensor Reference Voltage 2 Circuit Low
P0653 Sensor Reference Voltage 2 Circuit High
P0698 Sensor Reference Voltage 3 Circuit Low
P0699 Sensor Reference Voltage 3 Circuit High
P0700 Transmission Control System (MIL Request)
P0837 Four Wheel Drive (4WD) Switch Performance / Rationality
P0838 Four Wheel Drive (4WD) Switch Circuit Low
P0839 Four Wheel Drive (4WD) Switch Circuit High
P1652 J1850 Communication Bus
P2121 Pedal Position Sensor 1 Performance / Rationality
P2122 Pedal Position Sensor 1 Low
P2123 Pedal Position Sensor 1 High
P2127 Pedal Validation Switch 2 Low
P2128 Pedal Validation Switch 2 High
P2146 Fuel Injector Group 1 Supply Voltage Circuit
P2149 Fuel Injector Group 2 Supply Voltage Circuit
P2266 Water in Fuel Sensor Circuit Low
P2269 Water in Fuel Condition
P2502 Charging System Output Voltage
P2503 Charging System Output Low
P2504 Charging System Output High
P2509 ECM/PCM Power Input Signal Intermittent
P2607 Intake Air Heater Relay 2 Low
P2608 Intake Air Heater Relay 2 High
P2609 Intake Air Heater System Performance

as your code isn't on here I am guessing this isn't a complete list...

 

This morning when I started up at -27 below (it was plugged in all night long, of course) it fired right up and then ramped up to 1000 rpm's two minutes later. Never moved off the 1000 rpm's even when the grid heaters were cycling. I had a buddy who's 03 did just as you're explaining and the local dealer had to reflash the computer with an upgrade. The said they didn't know if it was the upgrade or something bad in the software but the reflash fixed the problem. Never happened since then....

 

C is a chasis code, P is powertrain

 

Looks like I'll need to take it in and have them check it out. I should also have them reflash the instrument panel to fix the infamaus intermittent check light issue also.

Anyway, thanks everyone for the info.

 

Mine does that. I have also noticed if I have my powerinverter on when the grid heater kicks on it will generally zap the power to the inverter. This all hapens at the same time the rpm's drop. I generally idle mine up to 1200 with a stck. At this rpm it will drop down to 800 or so. It sounds more to me like you are loading the engine up, like hitting a generator with a big load it pulles it down a bit. I am not worried about it, it quits when it is warm.

 

Silverramer,

Your "C 23 67" code is from the instrument cluster self-test. I assume you were holding down the trip odometer button when moving the ignition switch from off to on before receiving that code? You should have also received a "00 00" after receiving the "23 67"

The C doesn't mean anything other than maybe "cluster" since it is the result of the Instrument Cluster Self Test.

The 23 is "Headlamp switch input circuit open" (this is from the 2004 shop manual)

The 67 indicates how many on/off ignition switch cycles have occurred since the code was set.

To be honest, I don't know what the code 23 means exactly. Have you made any modifications to your headlight/fog light circuit? Did you have a blown headlight fuse about 67 starts ago?

 

handymantim,

You described exactly what I did and saw. No modifications to the headlight/fog light have been performed...yet..

We do pull a travel trailer occasionally which recently had low batteries. I wonder if related.

Anyway, thanks for the information. I guess I didn't know how to read the codes. I better invest in a shop manual.

Thanks again.