With this month’s issue theme being “Maintenance and Service Repair,” I felt there wasn’t much I could contribute on that topic. After all, I thought to myself, I am a diagnostician not a service tech! Boy, was I wrong!
I recently visited to a shop located about an hour from home that had a 2006 Jeep Wrangler with a 2.4L, automatic engine that shut off while driving and would not crank or restart. While en route, I noticed I was rapidly approaching the mileage of when my next service was due. How convenient, I thought! I could write an article describing how I do the maintenance on my own car and include a diagnostic story at the same time. But first, the Jeep.
The shop owner (who is also the lead technician) had determined the Jeep had a bad PCM, but wasn’t confident with his diagnostic skills enough to pull the trigger and purchase one, nor did he own the tools necessary to finish the job once the module was installed. That PCM needed to be programmed, but he had no way to do it. That’s why he called me.
As I was driving to his shop, thoughts were going through my mind of what maintenance should be done on my car and how they should be performed. I was approaching 150,000 miles, which in my book means all the fluids get replaced and the spark plugs would get replaced, along with the air and cabin air filters. I will be performing an induction system service, and I’ll inspect all the steering and suspension components, along with wear items like brake pads. I also thought it wise to ask this shop owner to please get my car on a lift (while I diagnose the Jeep) so I may see if there are any other things I might need.
I arrived and looked at the Jeep; I could read the PCM Module Information (showed this unusual P/N: 56044706AB.05), read data, read DTCs (four, all about failed control circuits), but could not have the PCM control the ASD Relay or have it perform any other bi-directional function when using Actuator Test Mode. The PCM would not ground the controlling circuits, yet there was less than .050 VDC on both ground circuits when back-probing the PCM connector while commanding activations.
Within an hour I came to the same conclusion as the shop owner, but not before performing the network tests the DRB III allowed. The network tests verified communication with all the modules that were fitted to the vehicle and showed me any DTCs that reporting modules had stored. I do this to make sure there isn’t some weird network problem that might be the reason for the no-start complaint. Everything was fine with the network. I was confident installing a PCM would solve this complaint.
Thinking ahead, the shop owner had a brand-new PCM waiting for me when I arrived. I was almost giddy with how smoothly this was going and was already thinking of getting an early start to the servicing of my own car. I definitely jinxed myself by doing so!
I was unsuccessful at programming the replacement module while using the MicroPOD 2 and both methods — DRB III Emulator and Chrysler-J2534. I was also unsuccessful when I used the CarDAQ Plus as the interface. I have a DRB III, but it is not communicating properly with my laptop, so I could not try the disk version of module flash (Benchtop Programmer). I know about the problems people have had using Chrysler-J2534 on Chrysler CAN vehicles, but this Jeep is not a CAN car. I reinstalled the original PCM and could not update that one either (but knew if it was already damaged internally the probability of a successful flash was low). All six attempts failed to identify the part number of either module. Having had similar results in the past, I suggested it may have been a faulty module. I left and waited for his call to say he had received a new module.
He did get a chance to get my car on one of his lifts while I was getting frustrated on the Jeep. He made a list of items he noticed that should receive attention that included a leaking left inner CV joint boot and an oil leak on the front of the engine. He inspected the exhaust system, steering components and the suspension and said everything looked good. On the way home I mentally went over his list and started getting angry because I remembered replacing the left CV shaft about six months prior with one I found online that was cheaply priced. Once home again, I couldn’t wait to lift the car and see for myself whether it was old grease that he saw or new. Was it just a small bit that could have been slung out of the clamp? Wishful thinking on my part!
On to my ride
I got angrier when I saw for myself what the shop owner saw. The inner CV boot was spewing its lubricant badly. I was angry at myself. I know you get what you pay for and cheap price equals cheap quality (in most cases). After seeing that, I went into my garage and retrieved the original CV axle that I’d had re-worked locally, just in case I would ever need it again, and added that task to my list of service maintenance I was to do in the coming days. Talk about irony; it cost the same to have my original axle reworked locally as it did to purchase the junk on the web!
The CV axle replacement went smoothly. It took more time cleaning grease that had been slung out of the CV boot than it did to replace the assembly. Then I focused on the reported oil leak. So much oil had leaked for so long that the harmonic balancer’s rubber sleeve had started to swell. I am uncomfortable seeing that much distortion on such an important component so I purchased an OE replacement and began determining where that leak was coming from.
Tracer dye helped me prove the valve cover gasket that I’d installed 50,000 miles prior was not the culprit! Instead, I’m saddened to say, the leak wasn’t a leak at all, but was the result of sloppy workmanship by careless lube technicians. No ultraviolet indications were visible after 1,000 miles of driving with the dye in the oil, yet the highest evidence was located around the top of the alternator and ran down around the front of the block. I was really hoping the oil filler cap seal was bad or something like that, but instead it was carelessness that was going to cost me a lot of money needlessly.
I got the call from my Jeep customer that the Chrysler dealer delivered a replacement PCM just about the time I was finishing replacing the dampener. The engine was sparkling clean, the belt replaced as a measure of insurance and the crankshaft balancer bolt was torqued to specs. I was ready to go!
Will the new PCM do the trick?
I arrived at his shop and headed over to the Jeep expecting to see the replacement module with the vehicle. When it wasn’t, I found the shop owner, who had them both on the bench and was concerned about the mounting holes being different from the original. He held them up to each other to show me the differences and I stopped him to show how the electrical connections were completely different! He hadn’t even looked at them because he was trying to figure out how he was supposed to mount it in the vehicle. I asked him to call when he got the correct module, and I’d return once again to finish the job.
During the hour spent driving home, I determined the agenda of what services on my car would precede the others in hopes the engine would cool down enough so that I could service the cooling system safely and change the power steering fluid without getting scalded. I decided to start with the work requiring the removal of the tires and wheels.
My first step was, while the engine was still hot, to perform the induction service. Why first? I’m about to take the spark plugs out, which requires the removal of intake components. Why not ensure I remove as much carbon before I begin?
Afterwards, I rotated the tires and properly inflated them but left them uninstalled in order to facilitate the flushing of the brake fluid system. I do this in the way the Hyundai service information recommends with a few exceptions. Instead of using DOT3 fluid, I use DOT4, a higher temperature tolerance and a low moisture absorbency (or LMA) fluid. I also use a scanner to activate the ABS motor and solenoids while the fluid exchange takes place. This ensures the complete removal of the old fluid and it gives me the chance to verify the proper operation of the ABS components.
During the draining process I open the bleeder screws, clamp the hoses only until the fluid flow stops, then push back the pistons in each caliper to remove the old fluid in their bores. This clamping of the hoses ensures I don’t push fluid back to the master cylinder or the wrong direction through the ABS components. At the same time, I can completely inspect the rubber caliper components and the brake pad wear surfaces, too! In fact, this time, I noticed wear on the rear pads that was sufficient for me to deem replaceable and did so. I cleaned and lubricated the caliper slide bolts and mounts, then reassembled everything. Once a hard brake pedal was felt, I reassembled the tire/wheel assemblies and torqued the lug nuts by hand to the specification. The last step was to ensure the master cylinder reservoir was full and the cap cleaned and tightened properly.
By the time I finished the brake work, the engine had cooled off enough that I could safely disassemble what was necessary for me to gain access for the replacement of the spark plugs. Before removing anything, I take an air blower and carefully remove any debris, dust sand, bugs, leaves, etc., from the work area so there is less likelihood they can fall into a place where they do not belong. The few minutes I spend cleaning the area I plan to work in saves me so much time!
This will be the third time the plugs were done. Yes, I know that the service interval listed is nearly twice what I was doing, but I’ll ask every reader one question: How much extra work is required when the spark plug replacement interval is so long that they weld themselves to the cylinder heads? I am too lazy to want to go through the work that must be done to restore spark plug hole threads (at best) or the removal of spark plug lower halves that were too stubborn to move as expected! I will perform this maintenance much more often than recommended by the manufacturer because I know they are in the business to sell parts and the cynical nature in me suspects that possibly, there may be a motive for recommending such a long interval.
Keeping the bad stuff out
Once the intake plenum is removed and set aside, I use individual cloth rags to fill the newly-exposed holes where air passes into the cylinders. I use rags of a different color than the ones I use to wipe my hands because when I am completing the task, I’ll count the rags to ensure they were all removed from their respective holes. This is like a surgeon making sure all the sponges and wipes are accounted for before the closing of the incision. Hey, why take any chances?
Before removing the ignition coils, I’ll blow the area down once more to ensure any debris that came from the removal of intake components doesn’t stay in my work area. Once the spark plugs are accessible, yup! You know it. I’ll blow into the spark plug tubes, just in case. Then I remove all the spark plugs and the rags used in the intake holes and blow in the combustion chambers through the plug holes to remove any carbon that dislodged during the plug removal. Why, you ask, am I so concerned about carbon and debris? It only takes one time that a foreign object enters the combustion chamber during a routine service for you to remember every time thereafter.
I always verify the gaps and electrode alignment prior to installation and if gaskets are required, confirm proper placement on the new plugs. If the box the plugs came in shows any sign of damage, you would be wise to ask for another or else you stand a chance the porcelain is cracked, maybe in a spot you can’t even see. I’ll use a 6-inch section of vacuum tubing that I push over the plug wire end of each spark plug that aids my installation of the plug in the cylinder head. Once started, I finish tightening them and finally, torque them to specification.
I’ll dab a bit of dielectric compound inside the spark plug boot before reinstalling each coil, then start each coil retaining bolt by hand. I’ll bring my half-inch impact to them and set it on its highest torque, uh, just checking to see if you’re still reading! Before reinstalling the intake components, I check all electrical connectors that will get covered. I ensure I didn’t accidentally knock any loose.
OK, you get the idea. I’m overly careful when I perform maintenance and service work. Believe it or not, I did the same for my customers’ cars as well when I had my shop (and when I worked for others, if allowed). For cooling systems, to mix with the pure antifreeze I get, I use distilled water instead of tap water. It is because you don’t want any minerals, metals or chemicals to contaminate the cooling system or else you are simply asking for trouble. I will research the fluids I use to ensure they meet or exceed every manufacturer specification. Again, why invite problems?
By the time I completed all of the work on my car, the shop with the Jeep called me and said they now have another new PCM — and that it is the correct one. I returned as soon as I could but found I was having the exact same problems as I was with the first replacement module! This time I started over. I verified every circuit attached to the PCM and performed micro surgery on the DLC terminals to ensure the best connection to the tool(s). I then re-checked the steps originally taken — like doing a network test again to confirm the bus is working as designed, performed the pin-out tests at the module, etc. I looked at every TSB Chrysler had published about reprogramming and about this vehicle.
The message "Acquiring Part Number" is the step where the reprogramming software hangs up on every attempt. Between the three tools used (and three methods), I couldn’t get any of the three modules to identify themselves in the programming process. No ID = No Flash.z
Twice through each reprogramming process I got a message, something like "Could not identify SCI A or SCI B" (but I’d seen that during successful programming events too). The replacement modules showed different DTCs than the original, but these also are displaying module information for a different type of vehicle (so codes should be expected). The PCM part number labels are different from the part numbers displayed in the scanner’s module information screens, too. About six hours were spent trying to configure this PCM to this vehicle. I gave up for the day, saying I’ll do some research on how to accomplish the task and come back by the week’s end.
I posted the problem in online forums asking questions from other professionals who might be able to share their similar experiences and offer ways to resolve this. Almost all respondents agreed with what I wanted to try. I told the shop owner the methods I thought would get the module to accept the flash. Unfortunately, a day later he texted me that the vehicle owner showed up unannounced to take his vehicle elsewhere! Sorry folks, this time I'd gotten trapped trying to resolve what should have been a simple PCM replacement but instead, it didn’t play by the rules, nor did the shop owner — and we won’t know which of the three ways I said I would try actually worked!
Oh and, yes! I counted those purple shop rags after reassembling my engine and before I turned the ignition switch. Think what kind of a horror story it would have been if I left one in the reassembled engine!