See this Mastertech issue for general information: Troubleshooting the 24 Valve ISB

• Tachometer/voltmeter/cruise control problems, check engine light, engine miss
  • 98-00 Crankshaft position sensor bad
  • 01-02 Camshaft position sensor bad
• Voltmeter reads low, Check Gauges Light and chime on.
  • Intake Manifold heater stuck on - check for stuck relay(s).
• Stalls when auto is shifted into drive
  • TSB 18-015-00 Rev A - reflash PCM
• Rough idle, Missing or stalling
  • TSB 18-15-00 - 99-00 Poor drivability with #1 fuel
• Idle Speed appears to fluctuate because Tachometer jumps around at idle - A fluctuation of +/- 50 rpm is normal because the computer periodically samples the engine speed and then updates the tach.
• Stumble or miss at operating speed - The ECT and IAT sensors must be accurate or the injection timing will be wrong.
  • If the engine temp gauge is not reading correctly, the ECT sensor should be replaced.
  • The IAT sensor may be dirty or inaccurate. See the IAT sensor page for cleaning instructions and typical resistance values.
• Low power
  • TSB 18-11-99 has been issued to slightly increase the engine power
  • If the PCM detects overboost or underboost (usually due to a wastegate problem), the fuel rate will be reduced resulting in low power. Check the boost under load - it should peak near 20 psi.
  • A fuel vent cap may have been left on the tank after assembly, and should be removed to prevent vacuum buildup in the tank. The fuel pump is unable to draw enough fuel against the vacuum and low power results.
  • Turbocharger diagnostic tips - from the Star Center News
  • TSB 18-21-99 provides acceleration charts to check for low power
  • Bad or weak lift pump - these have a nasty reputation for high failure rates. Minimum pump pressure should be 8 psi under all conditions.
• Poor Fuel economy
  • Bad or dirty IAT (Intake Air Temp) sensor. Dirty is a common problem, remove and clean the sensor.
  • Bad MAP sensor.
  • Low boost due to leak or wastegate problem.
  • Weak or dead lift pump
• Erratic shifting or incorrect shift points

  • most common source: the TPS (APPS) is bad or needs adjustment.
• Intermittent high engine idle condition
• Recall 799 - malfunction of the vehicle speed sensor causes sudden acceleration.
• Cruise Control speed changes or allows speed to drift
• TSB 18-08-99 - reflash the PCM
• No throttle response on the ISB
  • Bad or weak lift pump - these have a nasty reputation for high failure rates.
  • Timing gear 1 tooth off of its setting. (no PCM error messages generated)
  • Bad throttle position sensor
  • binding throttle linkage prevents full return to idle position - sets fault and disables control
• Hard to start or No Start
  • Engine hard to start when hot - Replace bad fuel lift pump and/or TSB 18-15-00
  • Engine hard to start when cold - check Intake Manifold Heater System
  • 00-01 Hard start and/or a no start condition - Service Action #00-11 replace fuel pump
  • 00-01 Ram failure to crank - see service action #00-01 for fuse revision
  • Intake manifold heater relay stuck - replace fried relay and/or heater grids
  • 98-00 Crankshaft position sensor bad - check this especially if the tach does not always work correctly
• Excessive engine noise
  • foam inserts on the inside of the front fender have fallen down. If you open the hood and look down into the opening(from above) at the top back of the fender, there is a large vertical oval hole(12"X 2") that opens into the door frame. On each side on the truck, a thick piece of foam should be plugged into the hole. Sometimes they fall down into the fender compartment. It is difficult to reach, so enlist help from someone with small arms.
  • a few reports of broken valve stems
• Buzz from the accelerator pedal when cruise control is engaged
  • TSB 14-04-98 - reroute throttle cable and add retainer clip
• Whistling or moaning from heater core/heater box area - caused by a coolant supply hose connector

  • for repair - see Star Center Note and TSB 09-04-99
  • Also described as a growling whirring sound and if I held the rpm of the engine at 1550...it would stay right there...sounding like it was coming from somewhere in the front of the truck.
  • Also described as a howling/warbling type sound most noticeable with a very light throttle and was most obnoxious around 2000 rpm..
• Headlights alternately brighten and dim after truck is started
  • normal, caused by high current draw of intake manifold heaters when temperature is below 60° F.
  • If the problem continues at speeds above 18 mph, check for loose terminals on the manifold heater relays.
• Voltmeter jumps up and down - Caused by intake manifold heaters cycling when engine temp is below 60 degrees.
• Heavy oil or crude oil smell - fumes are blown into cab from crankcase vent on front of engine
  • Relocate the blow-by bottle by extending the vent hose
• Oil Leak at front of engine
  • blowby bottle full; empty at each oil change
  • steep descent ( >23° slope ) will spill oil through the vent tube
  • Loose oil filters -  A series of revised oil filter numbers has been issued to address the problem.
• Low oil pressure - pressure gauge drops to 0 and/or warning buzzer sounds

  • Caused by PCM software failing to update the dash display in a timely manner. TSB 08-22-99
• Leaking fuel - line from the filter to the injector pump - details
• Recall 788 replace the line from the filter to the injector pump with Dodge p/n 05013876AA
• Leaking fuel, low power, engine miss
• see TSB 14-01-98A for design revision to high pressure fuel line
• Leaking fuel at fuel filter - 98-99 check the fuel heater connection on top of the filter housing, there have been leaks reported where the wiring enters the housing.
• Power steering pump failure in cold weather
  • More common than it should be -. If you regularly drive in sub zero (F) weather, you should allow the PS fluid to warm a bit before driving or install synthetic PS fluid.
• Overheating while towing: reports appearing of bad thermostat batch
  • replace thermostat : Cummins  P/N 3943200
  • see Dodge dealer for warranty replacement - no TSB yet
• Oil leak from vacuum pump drive coupling
  • A replacement seal is available from Reganis Auto Center, (308) 632-8200, seifert@reganis.com

Last update to this page: March 7, 2008