When your brake pedal sinks.

2001 Saturn SL1 : Brake pedal sinks complaint.
I found the brake pedal going to second stage and not sinking from there. Usually this is a hydraulic problem so you want to check the fluid level. If the reservoir is full, it may be an internal master cylinder problem. If the fluid level is low you may have a leak in the system.

The reservoir is empty but the area around the master cylinder is dry. We need to inspect the brake hydraulic system and look for where this fluid went.
We're looking for a wet spot. A leak at one of the wheels will usually show up on the inside of the tire.

In this case, right rear wheel.

This car has drum brakes in the rear and the fluid is coming from inside the drum so the leak will be a wheel cylinder.

The shoes have a lot of pad material but it is saturated with fluid. We'll need new rear shoes and wheel cylinders. The drum is in good shape so we'll clean and reuse. If we try to reuse the brake shoes after this fluid saturation they will tend to grab and not apply smoothly. The other rear wheel, which has dry shoes will apply differently as they no longer match. Brake shoes come in a set, replace as a set. The wheel cylinder on the left rear doesn't appear to be leaking but is the same age and conditions as the one on the right. If it isn't leaking now, it will soon be.

Now, this left side looks okay but we'll be replacing it and the shoes for the reasons I've said. I wanted to show you something else though while I'm here. Because there is no fluid visible on the outside of this wheel cylinder does not mean it isn't leaking. The leak has to get past those outer boots before it is visible. So peel the boot back and look for signs of wetness. If there is fluid inside the boot, the cylinder is bad.

Both wheel cylinders, all brake shoes, clean drums. Not finished inspecting yet either. Just as you don't want to do one wheel when both need service, you don't want to do only rear when front need service so we'll be inspecting the front brakes as well.

Pull both front wheels and inspect front disc brake pads, both inside and outside pad. No problems here.

Okay. Lets get some parts and fix these rear brakes!

Thanks!

Kenneth Hayes

khayes@ggauto.repair

Voltage Drop Explained

When One Door Closes (Battery Drain)

I love a good mystery!

A 2007 Ford Escape XLT 2.3 4x4 keeps draining the battery. After a battery boost the customer was able to bring it in. I put a low battery charge on it overnight. The first thing you want to know when looking for electrical system problems is that you have a fully charged, good battery. All of your testing is based on that.

Once the battery was fully charged I did a quick test that I had alternator output. Just watch that the voltage at the battery increases once the engine is running.

Next up was to test the battery but I would need to disconnect it from the car before testing because if there was a system on the car causing the battery drain it could interfere with the battery testing. I didn't want the system to lose power or memory but I didn't want it connected to the battery. Fortunately there is a tool for just such a situation!

The memory saver provides alternative power to the system so that I could disconnect the battery for testing. Just connect it to the diagnostic link under the instrument panel. There was no problem with the battery.

The battery was charged and good. The alternator was working. I put the cables back to the battery and disconnected the memory saver. After the basics checked out fine it was time to measure actual current draw on the battery. You have to allow a reasonable amount of time for system modules to timeout and go to sleep. If you start testing current draw while a module is active you will be looking for a system problem that isn't a problem but a normal condition. The amount of time that is reasonable varies. You can try a test after an hour, or less if you are in a hurry but if the draw is high don't get excited about it at first. Just wait another hour and check again. If you still see too much draw after three hours you are safe to go ahead and trace it down. I use an amp clamp to get the measurements so that I don't have to break a connection and trigger another wait for a timeout. This vehicle had two leads off the negative post. Depending on circuitry, the excessive drain can be on either lead so measure each one at a time.

I did have higher current draw on one lead than the other but 58mA isn't excessive. Apparently this was an intermittent problem because up to that point I saw no reason for the battery to be going down.

I mentioned that I try not to disturb circuits when testing for draw because of the added time waiting for timeouts if a system wakes up. I'm not sure if you are aware how a door latches but there is a striker on the body.

When you close the door the latch in the door closes over that striker and holds it closed until you release it with the handle.

Now a few cars still use door jamb switches to know when the door is closed. The closed door pushes a button in and from the position of the switch the system can tell the door is closed.

Most cars though, and this Ford Escape in particular use a switch that is part of the door latch to determine if the door is closed. Typically on a job where I'm trying to trace excessive current draw I'll be disconnecting things, removing fuses, etcetera and I don't want the added aggravation of triggering draw based on my opening and closing the driver door so I close the latch with a screwdriver and leave the door open. As far as the system is concerned the door is closed and I'm free to enter or exit as needed. Is that somehow related to quantum physics? The door is open, yet it is closed. No clue. Anyway there is a reason for expaining the door situation.
Since the problem was intermittent and not making an appearance at the time of the draw test I needed to take a look at the stored memory of the vehicle for clues. That possibility is why I had used the memory saver to keep the stored information from disappearing. I turned the key on and connected a scan tool and entered the vehicle information, preparing to scan the systems. When you turn the key on but don't start the engine there are warning lights that come on for a few seconds as a bulb check, then go out. I noticed something that looked odd here though. The door ajar light stayed on. I thought maybe it was because the engine wasn't running but it stayed on with the engine too. I had noticed the dome light was turned OFF early on. If I moved the dome switch to DOOR position it was staying on. Occasionally the warning light and the dome light would go off as they should but it never stayed working more than a few seconds at a time. I spent a bit of time inspecting latches and opening and closing doors. I know of a Ford problem with the latch switches getting dirty and sticking but spraying lube/cleaner wasn't making any difference.

I decided I probably had a bad door latch switch but I wasn't sure that would be the dead battery problem because the dome light was turned off and most Fords will time the power off before it kills the battery in that situation. My mind was thinking this anyway, lol. I did have the scan tool hooked up and ready though so I took a look. I had three "battery voltage low" faults. One for the restraint control module, the instrument cluster and one for the general electronics module (GEM) which on this truck has an alias of SJB or smart junction block. I didn't think low battery voltage codes seemed clues since the problem was a dead battery. I would clear those later but I decided to take a look at the GEM data because the GEM is in charge of monitoring those door latches. Maybe I could see which door the truck thought was open. Well that was interesting! There may be a problem with that right rear door.

Ford has the PATS, passive anti-theft system that is supposed to deter a thief stealing your car. The PATS system uses programmed ignition keys and most people are aware of it. There is also though a perimeter anti-theft system to deter breaking into the car. There are nuances but basically the perimeter system arms when you lock the car. If a break-in occurs it will set off an alarm with horns and lights and log in the system as an "alarm event". I'm not sure what the limit is on how many alarm events will store but here I had eight events stored and each involved the right rear door. I doubt that the problem was a thief repeatedly opening the right rear door. I'd thought it more likely that the door ajar problem was in that door latch.
I still wanted to pull up the right rear door latch data item but I found only front doors available on either the Solus Edge or the OTC Encore. I found the pid available on the Autel MX808 however. This is why you need several scan tools in this business. No one scan tool is going to be helpful in every situation. It's kind of like thinking you'll only need one wrench.

I removed the right rear door panel to access the wiring connector at the latch. The black wire with white stripe is the ground. The pink with light blue stripe is a reference voltage from the GEM. It the door is open the switch is open and voltage on the pink wire. If the door is closed the switch is closed and the pink wire goes to ground. The other two wires are for the power door lock.

If the reference voltage from GEM to switch was good and if ground to switch was good I should be able to open the door and see battery voltage on a meter connected at the switch connector.

So the GEM, reference and ground circuit to the latch switch were good. I wanted to see what the latch switch was doing. It is supposed to close and ground out the reference voltage when the door is closed. That didn't quite happen. The switch was doing a poor job. BTW the GEM still saw the 4 volts as an open door.

Bad door ajar switch verified. This is part of the latch and power door lock assembly. If I grounded the reference voltage myself by twisting the two wires together the GEM should see a closed door. Of course that would mean when you opened the door the GEM would not notice but the door locks would still work and no more phantom right rear door alarm battery drains.

In this case we did the fix that best fit the customer's budget. Case closed, er.. door closed.

Thanks for reading!

Kenny@ggauto.repair




 

The Buick Nailhead

Buick Nailhead V8

Benz Overfill

Benz Overfill

Mustang Is Not Cool

Mustang Is Not Cool

Mussing with the Mustang (code diagnostics)

Trouble codes. Stored trouble codes. Apparently the holy grail of diagnostics. "Buy a code reader so you can diagnose your car problem." Reading a trouble code and diagnosing a car problem are two different things. You can't tell that by looking around online though. When a customer asks about running a diagnostic, or how much are diagnostics, they are really thinking about plugging up a code reader or a scan tool. Diagnostics is seeing WHY there is a problem. Codes are saying there is a problem. Rather than telling you what is causing the problem, codes involve diagnostics themselves. You have to see why the codes are set.
1998 Mustang here in the shop to walk through on this topic. The car was said to be overheating, cooling fan not working, overflowing coolant, and at one time steam rolling from under the hood. A/C not cold and stopped working suddenly. An intermittent miss or cutout at steady road speed and Check Engine on.
The coolant was overfilled and because there was no room in the tank for expansion, it would push coolant out the overflow at times. There were no other coolant leaks and the cooling fan worked as designed. A lot of people think an electric cooling fan isn't working because the fan doesn't come on until the coolant temperature reaches around 220F and they don't wait that long. Nothing was wrong with the cooling system. No codes or scan tool needed for that diagnosis.
The A/C system was empty and the obvious leak was at the high side service valve which had sprayed refrigerant oil (and refrigerant) all over under the hood. Replacing the service valve, evacuating and charging the system seemed the fix. No other obvious leaks. No codes or scan needed for that diagnosis.
Now the "misfire". The car is running well and no obvious problem and they did say intermittent. This is when it might help to look at codes and scan data for clues.
I have stored memory codes:
P0136 which is a circuit fault code for the B1S2 (post cat) sensor
P1130 which indicates the fuel adapts have peaked for B1S1 (fuel control) sensor
P1131 which means B1S1 is showing lean fuel
P1000 which means someone has cleared codes and not all the monitors have run since that time
P1260 indicates a security system lockout, engine disabled.

Now, a cat monitor sensor isn't going to affect the engine performance under normal circumstances. The engine lockout is obviously not a current problem because the car starts and runs. The P1130 and P1131 could very well be related to performance problems. The P1000 could be important but only because it lets me know that some of the information that was previously stored is now missing. That would be information like other codes and other test results such as misfire history which I'm going to take a look at next.

I like to use OBDII Mode 6 / 53 Misfire Monitor to look at the misfire test results. The misfire monitor has stored misfire values for 1,2,3 and #4 cylinders and the exhaust does smell a little rich.

The conditions weren't met for the car to set cylinder misfire CODES but the "Value" counts are misfires seen during the monitor test.

There were no logged misfires on 5,6,7 or #8 cylinders. Noticeable is that all the misfires are logged on bank 1, the bank with the O2 codes for the fuel monitor. Since I can smell a rich exhaust but the code is for lean exhaust I am thinking the sensor is reporting lean and the computer is driving the system rich to compensate. The sensor isn't recognizing the richer mix. Theory.
Let's look.

At idle the right (bank 1) tail pipe is spitting out black carbon and has a rich smell. The sensor for bank 1 is showing lean at the same time.

The sensor could have failed and stuck lean (low voltage) but they also can foul from a too rich mixture so it could be the sensor failed and drove the bank rich or it could be the bank was rich and fouled the sensor. Either way it very likely has a bad 02 sensor at B1S1. Lets look.
Oh this looks fun.

Meanwhile days later.....
No it wasn't so bad to get out. Just looked it.

Let's see what the new one does.

If the sensor starts switching normally we are done with this part. If the sensor, which should now be working, starts showing rich then we know that the rich condition fouled the old sensor and we'll have to find the problem before it does the same to this one. In preparation we'll need to clear the KAM Keep Alive Memory, which will also clear the codes. If you clear the codes only it won't clear the KAM. Think of the KAM as learned programming. The KAM has learned to run bank 1 rich so we have to clear that out and let it start over. If we don't do that then the bank will still run rich until KAM updates the strategy which won't be now.
Signal now looks good.

Its a '98 with 122,000 miles on original cats. I doubt they work very well but we have that B1S2 code left over right? Bank 1 had the problems and that rich mixture going through the converter could have caused problems further downstream. What we'll do there is drive this enough to get through some monitors, look for pending codes and then see what the cat monitor sensors are doing.
Sometimes a bad cat will start working after you give it a good fuel mix and that rear sensor on bank 1 may be fouled right now like the front sensor was. Drive and test again after.
....................
The B1S2 sensor did begin showing activity but wasn't working properly so I replaced with new.

If you want to get an idea of how well a cat is working you look at the fuel monitor sensor (which is exhaust before it goes into the converter) versus the cat monitor sensor (which is the exhaust after the converter). Generally speaking, the more your cat sensor mirrors the fuel sensor signal the less efficient your converter is. These are actually working enough to keep from setting a code.

So, diagnostics is not code reading and code reading is not diagnostics. Diagnostics is about knowing how a system works and about how to find why it isn't.

I think we deserve a pat on the back for this job well done!

Thanks for reading!

Kenny@ggauto.repair

Ford Escape Seat Track Rust tsb

tsb for seat track rust 09-12 Ford Escape

Scheduled Maintenance: Normal or Severe?

If you have ever looked at your manufacturers maintenance schedule you may have noticed there is a "normal" service schedule and there is a "severe" service schedule. Most people figure they fall under normal service and follow that schedule. If you ever read the definition for severe service though, you may find your vehicle use falls into that category.
A 2002 Chevy Silverado for example has an odd way of determining which schedule to use. "Follow the NORMAL schedule only if none of the conditions from the SEVERE schedule apply."  Italics are mine. (ONLY IF NONE). So, if ANY of the severe conditions apply to your vehicle use you should be using the severe schedule. Let's look at the "severe" conditions:

Follow the SEVERE schedule if any one of the following are true:
Most trips are less than 5 to 10 miles.
Most trips include extensive idling. (such as frequent driving in stop and go traffic)
The vehicle is operated in dusty areas frequently.
Trailer towing or using a carrier on top of the vehicle frequently.
The vehicle is used for delivery service, police, taxi or other commercial applications.

Remember, if any ONE condition is applicable to you then you are in the SEVERE condition schedule definitions. Interesting huh?  I'm not sure what the differences are on the schedules themselves. Spark plug replacement isn't a huge difference. In fact, it is a little odd. Normal suggested spark plug replacement, 100,000 miles. Severe 99,000. ?? Thats weird. I would expect oil change to be different. Lets see. Replace oil at 3,000 under severe or 10,000 under normal. Huge difference there. Good time to note, oil change is not the same as oil check. Check your oil level occasionally between changes and if it needs oil, add oil. But never try to top off oil if it is less than a quart low. Wait for it to be a quart low, add a quart.

Moving on.

2008 Ford Escape. The Ford severe duty is called special operating conditions. Towing a trailer, using a camper or car top carrier. Extensive idling, low speed, commercial use (taxi, police, delivery). Operating in dusty conditions. Off road operation. Use of E85 50% of the time or more (flex fuel engines). I was curious about the spark plug change schedule here because I had one with 112,000 miles that the plugs were original and severely worn. Normal oil change intervals are at 7,500 and plugs at 90,000. Severe schedule is oil changes at 5,000 and plugs at 60,000. Ford says if you are operating at any of the severe duty conditions only rarely then you can stay on the NORMAL schedule. Good to know.

Let's jump it up a bit to a less older car. 2011 GMC Acadia. This was in recently also with original spark plugs at 180,000. I would say they don't pay much attention to scheduled maintenance but let's take a look. The service definitions are the same as for the 2002 Silverado. Normal schedule has oil changes at 7,500 and spark plugs at 100,000. Severe is oil at 3,000 and plugs at 100,000. No difference then as far as plug change. Only 80,000 miles past recommended replacement. No wonder it was misfiring.

Well that was some fun huh? Something to think about anyway. Have a good weekend!

Kenny@ggauto.repair

Lean Codes: 2002 Silverado

2002 Chevrolet Silverado 5.3 vin T comes in with MIL on and lean codes for both banks. Complaint is that the engine doesn't run well.

Other than codes stored I don't see a problem. The truck seems to run fine other than an occasional sputter at idle.
Lean conditions can be either caused by too much air in the mix (vacuum leak) or not enough fuel (fuel delivery). Next step is to determine which is the case. If the system goes lean at high fuel demand then the problem is with fuel delivery. Easiest way to determine a problem there is to drive the truck at road speed and accelerate hard. Notice if the truck loses power and record O2 activity. In this case the truck had great acceleration and O2 for both banks showed plenty of fuel in the mix under high demand.

The other side of the coin would be a vacuum leak. A vacuum leak would drive the mix lean at low rpm, low demand and at the present time, with the warm engine. I wasn't seeing a problem there either.

The thing is though, I happen to know these engines have a common problem with intake manifold gaskets allowing vacuum leaks when the engine is cold and sealing once the engine is warm. I could let the truck sit overnight and look for vacuum leaks on the cold engine. Usually you can monitor short term fuel trim while spraying carb cleaner at the manifold base and if the spray gets pulled in the fuel trim will drop dramatically.
There is another option though. Freeze frame data is stored when a code sets and captures data that was present at the time. So if we look at freeze frame and see a cold engine, low load and low rpm that means vacuum leak. It would also indicate the vacuum leak was the intake gasket problem.

That is enough evidence to warrant removing the intake manifold. Definitely bad intake gaskets.

Hopefully this will also help with the poor running complaint. At any rate, the vacuum leak is fixed.

Thanks!
Kenny@ggauto.repair