2000 Toyota Sienna CE : Intermittent No Crank

Got this Sienna in the shop that sometimes has to be boosted with jumper cables to start, according to the customer. It has been looked at by other shops but no cause found. I noticed the battery is a Toyota brand dated 11/17 so not very old. The car had just been jump started to drive here and I pulled it inside still running. After parking and shutting off I put the charger on and saw a 69% charge. I let the charger stay on until reaching 100% late last night. This morning I did a quick reconnect and saw the battery back to 90% so I'm already suspecting there is a drain.

That hunch turned out to be wrong. 

Back to plan A then. I should have enough charge to do the battery testing. I'll start the engine a few times with lights and accessories on to dissipate any surface charge and get a more accurate test. Also, I like to disconnect the battery terminals and test directly from the posts with no possibility of the car wiring affecting the result. Since I'll be disconnecting the battery I like to put a memory saver in place to help the car retain system memory. 

Well the current draw is in within specs and the battery tests good (but is still a bit less than a full charge). I'll check the alternator output, put the charger back on to get 100% again and monitor this thing for a day or so. Meantime I can check for related bulletins. Hold on. Found a problem. I put the old battery load tester/meter on for a quick check. Battery still tests good with load test but the alternator is barely registering. With no accessory load it is not a good charge and with accessory load it sometimes drops to no charge at all. Retesting with a more accurate tester and yes the alternator is indeed bad. Belt is still original as well. 

Summary: I need an alternator and a drive belt, battery charge and a follow-up system test. 

Thanks for reading

Kenneth Hayes

G&G Auto Repair

A/C Testing

Just a quick walk through and reminder of A/C system testing. The complaint on the 2006 Sonata was the A/C was not cold. Checking the settings, they were fine for testing. You want the system set to coldest temp, a low blower speed and recirc (max) airflow. Put a thermometer in the center dash vent and look for A/C output to at least be 50F. Depending on variables like how long the car has been sitting in the sun, how hot the outside temps are, and such. You might have to drive a bit to reach coldest vent temps but this particular car was getting down to 40F with no driving at all other than from the parking area to inside the shop.

I don't see a problem. That is certainly cold enough. A test drive would be in order to determine if the problem is related to conditions that happen while driving. But while the car is inside it would be a good time to check the actual refrigerant charge. The customer had mentioned adding refrigerant himself. Usually that involves one of the A/C charge kits sold over the counter at so many parts stores and box stores. One of the problems with using the kit is that you have no idea whether the system is properly charged either before or after you use it. Personally, I don't see the point then. But if we didn't spend money on something we'd all be wondering what to do with it right? Anyway.... I connect the recovery/recycle machine and open both gauges. I recovered 1lb 9oz of refrigerant. The system was overcharged by 6oz.   

With a proper charge and a road test the A/C still operated as designed. Could the overcharge have been the problem? Yes. More is not always better. The pressures would not be correct and could cause the compressor to cycle more often than designed. Or, there could be another problem lurking in the shadows that has not shown up while the car was here. I just advise the customer and we see how that goes. 

Thanks for reading 

Kenneth Hayes

G&G Auto Repair

How Does That Work Series: Testing A Battery Drain Problem

A common complaint is a battery going dead after a car has been parked for a day or so. I just happen to have a 2013 GMC Sierra in the shop with that problem. I'll walk through the steps to diagnose this particular truck. First, we want to be sure the battery is fully charged and is a good battery. The electrical system tests aren't reliable unless we are using a good, fully charged battery. The battery had a 90% charge when the truck came in. A slow charge is needed to bring it up to 100% and that can take a few hours. Sometimes I switch batteries to let the original charge while I use a known good battery to move ahead with the tests. This truck was staying overnight so I just left the charger on the truck until it reached 100%.

After the battery is charged, it should be tested. Cranking the truck a few times with lights and accessories on will get rid of the surface charge so the test will be accurate.

Once the battery has been verified good and has a full charge it is time to measure the actual current draw. I like to use an amp clamp along with the meter so that I don't have to disturb a circuit.

You have to let enough time pass that the computers should go to sleep mode. If you start testing before that time you will be chasing a draw that isn't a problem. After waiting an hour I put the clamp on the negative battery cable and I can see excessive current draw. 

At this point the job is to find the circuit the problem is on. I had a small ground wire from the battery post with no draw and the large one with 377mA. The positive post had three cables from the positive post. I found the draw to be on the cable from battery to underhood fuse block. 

Next step is to start removing fuses from the block one at a time and watch the meter. When you see the draw fall to normal you have found the circuit and are a step closer. I like to take a picture of the fuses while all in place in case I have to refer to it when re-installing the fuses. As I remove each fuse I lay them out in a similar pattern but the backup of a picture is a good idea. If you remove a fuse that has no affect on the draw don't put it back in immediately. Just keep removing fuses and laying them aside until you find the one that affects the problem. Putting a fuse back in before you have found the problem can sometimes wake a computer that was in sleep mode and you will have to allow the timeout all over again. 

Eventually I did find the fuse for the problem circuit. I like to put the other fuses back after I know where the problem is and just leave that one out. 

Next up is a wiring diagram. It is sort of a roadmap for tracing further. We want to see what this fuse feeds. This fuse turns out to be the battery feed to the instrument panel fuse block. So I put the fuse back in place. We'll have to wait for the timeout again but I also had to leave the driver door open to access the instrument panel fuse block. The door is open but tripping the latch closed is enough to make the computer believe the door is closed. 

Just like the procedure for the underhood block, we'll pull fuses in the instrument panel block until we find the circuit with the draw. I found the problem circuit and left that fuse out, replacing the rest. 

Then it is back to the wiring diagram. The fuse powers the Vehicle Communication Interface Module. (OnStar Module). 

Having gotten this far I was able to find a related service bulletin. 

You will find different paths on different automobiles but the procedure for tracing battery drain is going to be basically the same. Thanks for reading!

Kenneth Hayes

G&G Auto Repair

Sometimes I have cold A/C, Sometimes not

This was a 2000 Nissan Frontier. The complaint was that sometimes the a/c seemed cold, sometimes not. The air felt cold enough when I drove the truck into the shop. A quick test to find max cool temperature is to turn the temp control to coldest, fan to low speed, max a/c or recirc setting and put a thermometer in one of the center vents. Generally speaking, a good system should output 50F or colder when driving at road speeds and set as written above. Automatic temperature systems will change output temps once the cabin reaches the setting you have in place. Until then it will output the coldest air.
The vent air on this truck was moving between just below 50F to just above, as the compressor clutch would cycle. I wasn't driving at road speed. I was just in the shop holding rpms at about 1800. The clutch was cycling a little more often than I would have expected and the output temp was just at acceptable range so I decided the refrigerant charge, while it could be slightly low, wasn't the cause of the complaint.

I let the truck continue to run with a/c on for several minutes before the problem appeared. The air had stopped cooling and the compressor clutch had disengaged. 

The system had sufficient pressure according to the gauges. 

Testing at the compressor clutch relay showed no command from computer to close the relay. 

I needed to see if the computer was aware there was no command to the relay so took a look at scan data. The computer was seeing a/c request but was keeping the relay off. Verified by scan data.

Since the computer was intentionally turning the compressor clutch off I would need to look at other data items for something that could be causing the problem. I checked stored codes and the check engine light was on from the beginning. None of the codes seemed related to the a/c problem. Going back to data items though I saw the engine coolant temperature was above normal. 

The computer was turning the compressor clutch off to prevent engine overheating. I added a half gallon of coolant to the radiator and the same amount to the recovery tank. I found no leak even with a pressure test but will be keeping an eye on this one. The actual refrigerant charge was 3oz less than a full charge so did make a difference in the a/c temp as well. Here are the final pics after the work. 

Thanks for reading!!

Kenneth Hayes

G&G Auto Repair

kenny@ggauto.repair

How-It-Gets-Done Series: Checking A/C Refrigerant Charge

The weather has been pretty crazy lately but a few days have spiked upwards in temperature enough that A/C jobs are coming in. Getting the jump on the summer heat does seem like a good idea if your A/C isn't performing as it should.
A common request is to charge the system because it is probably "low on freon". Most of the time a check of refrigerant charge is exactly where to start the diagnostics. Here is how that process happens.
We'll roll the refrigerant recovery/recycle/recharge machine over to the car and connect the machines hoses to the proper service valves on the car.

When I open the service valves I can see the system pressures on the panel gauges. These pressures were on an actual car in for A/C service. The connections were made. The valves opened and please note the gauge readings.

Does this system need added refrigerant? I have no idea and that's my point. Have you ever seen those A/C Recharge Kits in parts stores or other stores with a can of refrigerant and a hose with a gauge? The hose will attach to the low side port of your system and the gauge reading is supposed to be how you know if the system needs a charge or is full. That is not how it works. But lets move on.

The way to find how much refrigerant is in the system is to "recover" using the machine.

There were 9.oz of refrigerant.

Refrigerant charges are based on weight. We recovered 9 ounces of refrigerant and pulled a slight vacuum on the system. A full system charge is 1.35 lb, or 21.6 oz.

The vacuum is a result of the refrigerant being drawn from the system. By allowing some time to pass (work on other things) and watching for any loss of vacuum we can get some idea of whether there is a serious leak present. We know there is a leak because the system was low. We just don't know how bad the leak is. After about a half hour the vacuum reading was unchanged. I had noticed the system had a refrigerant dye. With a dye present we can look through yellow tint glasses and use a blacklight to spot leaks.
With a light but no glasses......

Through the glasses (hence the blurry shot) you can see leaks at the seat of the pressure switch and at the bottom of the high side service valve.

There are also compressor leaks.

At this point there was a discussion with the car owner. It was decided to replace the service valve and switch. We pulled a full vacuum on the system and again allowed some time to see if it held.

The vacuum held and the system was fully charged to specs.

The system pressures with a full charge.

That is how to properly check and charge an A/C system with R134a. Those small cans and those charge kits...... just say no. On a similar note, NEVER put anything that says "leak sealer" or "stop leak" into your A/C system. At the very very best, it won't damage anything. It won't fix anything and when you do have to get the repair done it will damage my expensive recovery machine! No car manufacturer wants stop leak in the system.
There are lots of things to go wrong with A/C systems. 85% of the cars in for A/C work do have full systems but have other problems. Here I've just touched on low refrigerant and leak detection.
Hope you found it interesting. I have more and I enjoy talking shop.

Thanks for reading!

Kenneth Hayes
G&G Auto Repair