Dodge Engine Light Questions And Answers

Welcome to the Dodge engine light Question and Answer Page! This page should save you some time from submitting a duplicate question and having to wait for a response. If you can't find the answers you're looking for here, feel free to submit your own by using our "Get Help" link, or for immediate solutions, see our Wiring Diagrams page. We will include the model in most questions, so you can use the "Find on this page" function of your browser's "Edit" menu to get relevant info for whatever check engine light concerns you may have.

For instance, just type in "Ram" and search for responses relating to this vehicle. You could also type in a Dodge engine light code number by itself such as "P0442" to get all related responses for this trouble code. Just keep hitting "Find next" to go through all relevant check engine light responses. We don't recommend including a model year as this may make your search too narrow, and you may miss out on some relevant posts. Our Dodge engine light resources cover a very wide range of concerns, but if you still can't find what you're looking for through these links or our code listings, then visit the check engine light "Get Help" link on the navigation bar. As always, all repairs should be attempted only by a qualified individual. Please read our Disclaimer before getting started. Thanks for stopping in, and we hope you have found something helpful from our site!

Question:
I have a 2003 Dodge Ram 1500. I have a check engine light with DTC codes P0442 and P0455. What exactly causes these Dodge engine light codes, and how do I fix the problem? What needs to be replaced? I have already replaced the gas cap and this did not fix the problem as the check engine light is still on.

2003 Dodge Ram 1500

Answer:
I think I can be of assistance. A Dodge engine light code P0442 indicates that a medium sized leak has been detected in the evaporative emissions system. Code P0455 indicates that a large leak has been detected. So basically the same concern is likely causing both check engine light codes. The evaporative emissions system is responsible for controlling fuel vapors, and metering them into the engine to be used in combustion and reduce overall vehicle emissions. The computer actually has a test that it performs on this system under certain conditions to make sure that there are no leaks, which would allow these vapors to vent to the air and pollute the environment. These conditions include cold start, engine running with fuel level greater than 12% and outside temperatures between 39 and 89 degrees Fahrenheit. When performing this test, the computer activates a Purge Solenoid to bring the system under vacuum. Once the NVLD (Natural Vacuum Leak Detection) switch is closed, indicating that a vacuum is obtained, the solenoid is turned off. If the vacuum level drops off, indicating that there is a leak in the system, the computer will set these codes. The rate of the leak determines which codes will be set. If you have replaced the gas cap then you can most likely eliminate that as the leak point. I would suggest taking a close look at the filler neck to make sure there are no cracks, and that there is a smooth surface for the gas cap gasket to seal against. A repair shop will hook a specialized smoke machine up to the evaporative emissions system and close the evap solenoid vent line. They will then fill the system with smoke and check with a spotlight for leaks. If no leaks are found it is possible that there is an issue with the purge solenoid. You can perform a quick mechanical leak check on this solenoid by disconnecting the vacuum lines from it and applying a 10 in Hg vacuum to the "can" side of the solenoid. It should hold vacuum. If not there may be an internal concern. Most often a leak in one of the lines or fittings is the cause of the problem and repair is fairly quick and inexpensive. You can do a visual on the lines yourself before bringing it to a shop. The EVAP leak detection pump, filter and purge solenoid can all be found together at the passenger's side front fender. The filter is the cylinder type device and the purge solenoid has the double vacuum fitting and electrical connector going to it. The pump should have a vacuum line on top and a couple of larger EVAP lines towards the front side as well. Check all lines at these components and follow them to their destinations, looking for signs ot wetness, leaks or cracks. Repair as needed. Use standard safety procedures and equipment. I hope you have found this information helpful. Let me know if I can be of any further assistance! If you've enjoyed our site and found it useful, consider referring a friend. Thanks for visiting!
Mike
www.engine-light-help.com


Question:
I have a 2002 Dodge Ram 1500. My Dodge engine light is on. What can I do about trouble code P0601?

Answer:
Welcome to our site, and thanks for submitting your Dodge engine light question! This code indicates an internal PCM (computer) controller failure. If this check engine light code is present during a self test, the PCM has an internal failure and requires replacement and programming of the new module. I would recommend calling the dealer directly to see if there are any known issues relating to this code before replacement, as computer failure is uncommon. Thanks, and let me know if I can be of assistance with any future Dodge engine light concerns.
Mike
www.engine-light-help.com


Question:
Hello at Engine Light Help. I was wondering if you could shed some light(no pun intented) on the following Dodge engine light codes and possible fixes which I retrieved from my Dad's 2002 Dodge Dakota with a 3.9L engine. The truck had been experiencing a hard starting problem so he had the throttle body cleaned. The truck seems to be starting and running fine now but the engine light has now come on and has remained on. I found two codes stored by using the key off/on method and they are P0138 and P1282. The first code, P0138 judging by what I have read, looks like a high voltage in bank one of the Ho2S circuit after the cat/conv, or what you refer to as the monitor. The second code shows a possible short or open in the fuel pump relay control circuit. Just wondering if the fuel system cleaning could have something to do with these Dodge engine light codes being set and if you have ever run into both of these codes together. I have also seen the second code (P1282) listed as a Pedal Position Sensor 2 circuit low voltage fault on other sites. Any help is much appreciated.

Answer:
Thanks for submitting your Dodge engine light question! I think I can help. The P1282 trouble code is set when an open or shorted condition is detected in the fuel pump relay control circuit. There are a number of possible causes for this code including a faulty fuel pump relay, open or shorted fuel pump relay control circuit, open in fused ignition output circuit or internal PCM concern. If the vehicle is running then that means that the power circuit is functioning okay at this time. You may have an intermittent, but more likely than not this code was set from the engine stalling previously. Most tests neglect to mention this as a possible cause, but these Dodge engine light codes can often be set as a result of a stalling concern, so I would clear and disregard this code unless it returns. Moving on to the P10138. This code is generated when the computer (PCM) detects a voltage greater than 1.5 volts on the signal circuit of sensor 1/2, which is the sensor after the converter. You are correct in your conclusion. This is an electrical concern that can be caused by a wiring problem, faulty Oxygen Sensor, ASD (Automatic Shut Down) relay concern or internal fault with the PCM. If you disconnect the oxygen sensor (monitor) and look at the vehicle harness side you should have 4 different color wires: pin 1 is Orange/Dark Green, pin 2 is Violet/Orange, pin 3 is Black/Light Blue and pin 4 is Tan/White. The Black/Blue wire is sensor ground provided through the PCM. The Orange/Dark Green wire is power provided through the ASD relay. The Violet/Orange line is for the PWM (Pulse Width Modulated) heater circuit which also runs to the PCM. The Tan/White wire is the Signal Circuit that runs to the PCM, and is the circuit we are most concerned with. These specs are for Federal Emissions vehicles, California emissions may differ. The computer knows that O2 Sensor voltage should be between 0 and 1 volt, so it sets this Dodge engine light code when it sees a voltage greater than 1.5 volts. Check for signs of chaffed, damaged or shorted wiring. We always recommend verifying information with an appropriate manual when dealing with any Dodge engine light issues. If there are no wiring issues and all circuits on the vehicle side are operating normally, then most likely the Oxygen Sensor is faulty. There are a few presumptions we can make during our testing: the sensor ground out of the PCM is common to many sensors, so if there is a problem in this circuit it will not likely be internal to the PCM, but more likely between the splice point in the harness (S101 at rear of engine) and the sensor connector. Also the same applies to the ASD power feed line as upstream and downstream Oxygen Sensors use the same line up to splice S136 (also at rear of engine). So if there is a problem with this circuit it will not likely be the relay or any part of the circuit on the power side of the splice. Problems involving these components would likely set other codes for sensors that share this ground or power circuit. I hope this is not confusing, but deductions such as this can save lots of time diagnosing wiring problems! So if pin 4 of the Oxygen Sensor were out of the connector and the key was on, you could check for voltage at the harness side. If there is voltage then you know there is a wiring issue such as a short. If not then the vehicle side is probably okay. You could also check at the sensor side of the connector and see if there is a voltage above 1.5 volts letting you know the sensor is likely shorted internally (if all else tested out well). Testing such as this should only be practiced by qualified individuals and proper safety measures must be taken. I hope this information has been helpful! Let me know if you need any help with future Dodge engine light issues.
Mike
www.engine-light-help.com


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