Mar 222020

GMC Yukon

I have replaced 2 rear brake lines from ABS Module to rear brake. Plus replaced Master cylinder with active control. Bled the farther rear line, then the next rear left. Then Bled the right front brake and last front left. But I’m not getting pressure to the brake petal, it goes to the floor. What can be the problem. I don’t have a scan tool for ABS Module. Can it be a fuse? or is it the module? or do I continue to bleed the lines?
Thank you for your help it is very much appreciated!

Did you bench bleed the master cylinder before installation?

Lets will assume you did. The brakes on these are pickier than any other brakes I have worked with in 30 years. I have had a time trying to get a brake pedal on the 2006 Chevy trucks. I replaced the brake brake lines with stainless steel and couldn’t get a pedal no matter how many times I tried to bleed them. But fortunately I am not one to give up easy.

I even dove into the thinking it was the ABS Module bleed issue. No it was not. A work around is just getting it to activate and it is considered bled. This is of course if you do not have a scan tool.

How to get the brakes to bleed

It turns out that the only way I could get the rear wheel cylinders to bleed all the air out was to over adjust the rear brake shoes (This was also done after replacing the rear brake shoes). I had to tighten the shoes all the way and then bleed the brakes. Then test and adjust the rear shoes. I know it sounds odd, but you will see these shoes like to be tight.

After doing this the brakes worked just fine. Before this I was having to pump the brake pedal to get it to stop at all. Yes, I too replaced the master cylinder.

Mar 122020

Chevy Cruze

Hello, I have the p4020 code on my code reader so I’m going to change the catalytic converter but I’m kind of confused and I don’t know anything about cars. Can I get just the catalytic converter by itself or do I have to get one that’s connected to the exhaust manifold? Thank you for your time and help.

I think you intended to say Code P0420.

You can purchase a universal catalytic converter but it will have to be welded into place instead of bolted. And it may take some serious fabricating that in turn may end of costing more money. Not to mention it will take more time. No need to buy the entire manifold either.

An OEM Catalytic converter would be the best way to go for most individuals that aren’t equipped with welder or welding skills. Like this Front one available form Amazon: Davico 19518 Catalytic Converter

Gaskets are included with this catalytic converter. Made in the USA but not legal for use in California.

Not what you are going to need but just for example. Here is a picture of a rear catalytic converter for the 2013 Chevy Cruze:


Labor Time for 1.4L Chevy Cruze Catalytic Converter
Model Year Skill Code Factory Time LABOR Time
 Cruze, Cruze Limited,
   Front ………………………….. 2011-16 B 0.6 0.8
   Rear …………………………… 2011-16 B 0.8 1.1

Before you make a purchase take the time to look at what you have and what you need and order accordingly.

Mar 102020

2011 Chevy Cruze

I drive a 2013 Chevy Cruze. My check engine light came on. The codes are P0324 and two instances of P0496. Is it possible for me to buy a part and replace it myself, or will I have to take it to a shop?

The two codes are not related. They are completely separate systems. So each code will need to be diagnosed separately. With that in mind I try to approach the issues by looking for anything that might be in common with both codes. And looking my first thoughts are bad fuel. Having contaminated or poor grade fuel would cause the knock sensor to set a code and may also cause a EVAP Code.

What can I do?

Drive the vehicle easy until the fuel tank is below 1/4 tank. Then at a different fueling station, fill up with high octane. This will mix with what is left in the tank and bring down the Octane level in the process. So make sure to chose the highest octane available. It will then take 10 to 20 miles for the fuel to mix and flow through the already full fuel filter. At that point you can clear the codes and test drive to see if the light comes back on.

Should the check engine codes reappear you will need to approach each code separately.

Chevy Code P0324

Code P0324 Knock Sensor Control Sensor Error

The knock sensors enable the engine control module(ECM) to control the ignition timing for the best possible performance while protecting the engine from potentially damaging levels of detonation. The knock sensors produce an alternating current (AC) voltage signal that varies depending on the on the vibration level during engine operation. The ECM adjusts the spark timing based on amplitude and the frequency of the two knock sensor signals. The ECM receives the two knock sensor signals through 2-isolated circuits. The ECM learns a minimum knock sensor noise level for all of the engine speed ranges. The ECM monitors for a normal knock sensor signal. The ECM monitors the two internal knock sensor processors by verifying a 20KHz signal generated on the signal circuits is detected on the sensors’ low reference circuits.

Action taken when Code P0324 is set

The ignition timing is retarded to reduce the potential of engine damaging spark knock.

Chevy Code P0496

Code P0496 EVAP System High Purge Flow

Mar 032020

2005 Chevy Trailblazer

I can’t find an engine fuse box for the trailblazer but would one of these fit in my trailblazer?

RAINIER 05 5.3L”,”ENVOY XL 05 5.3L”,”ENVOY XUV 05 5.3L”,

The seller of a fuse box unit 15210962 Module 151-9c3 states that the Envoy and Trailblazer are similar.
For Reference Only:
2004-2005 GMC Envoy Fuse Box Relay Unit
2004-2005 Chevrolet Trailblazer Fuse Box Relay Unit
Please make sure to match the part number of the item with the one you have. All computers have to be reprogrammed through dealership. We do not provide reprogramming service. We are also not responsible for any kind of labor cost or reprogramming cost.
Feb 282020

Chevy Cobalt

Was wondering if you have any information regarding the wiring harness as shown below. Was looking for any PDF documents referring to the electrical diagrams. Also as where I can purchase the connector / cable shown below. Keep in mind, the connector / harness I am referring too plugs into the 645-205 black female connector shown in the amazon link. The connector I am trying to purchase with harness is what is shown in the first picture and on the right in the second picture.

Dorman 645-205 Pigtail Connector-Headlight

body wiring harness 1
2008 chevy cobalt wiring harness

Not sure of any documentation on this. However I think i can help with this. The wiring harness would be referred to as the head light/lamp wiring harness.

Part No. For 2008 – 2010 Cobalt OEM GM Head Light Wiring Harness is 20760562 on eBay is only a small socket, do not purchase this thinking you will get the entire wiring harness.

2008 Chevy Cobalt Headlight Wiring Diagram

Therefore, in order to get the correct wiring harness you may need to contact your local dealership. There is of course the option of going used at a junkyard.

Feb 102020

Chevy Cobalt

Big hole in Transmission pan, drove it home full throttle, I replaced the pan,and gasket and filter,fluid,But noticed that the trans bands intermediate and reverse were burnt because of what I found in the old trans pan. replaced both bands,and replaced pressure sensor solenoid valve-out put speed sensor, problem now it will not recognize any gears.runs great no noises,the only way the thing will work is by applying the brakes , reverse lights work.its on a 2010 Chevy Cobalt , Transmission is 4T45E, please help it won’t move when giving it has.

I worked before and now it doesn’t. So the first thing to do would be to double check your work and see what is no longer in the right place. Check for anything left unplugged as well. Scan for any trouble codes present that might help narrow down the problem area. No quick fix for this one.

Wont go over 20 mph 2002 Chevy Blazer 4.3L

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Jan 312020

Chevy Blazer

just over 60,000. It had been sitting for 7 years. I have dropped and cleaned the gas tank. Replaced fuel pump and fuel filter. I have also replaced the plugs, wire, cap, rotor and air filter. Then I had to replace the spider injection system since it had sat for so long also replaced the IAC. It will start with little effort and idles around 600. If I give it gas it bogs down i can work the throttle and get it up to 2400-2600 rpm but will not go past that. I drove it up to the gas station and filled it up with mid grade fuel and a bottle of sea foam. Could not get it over 20 mph and any time I got on the throttle it would bog down and try to die. I thought that since it sat so long maybe the muffler had something living in it so I disconnected it and still no change. Then I am at a complete loss on what to do next. I ran codes and had the P0300 after driving it but since I cleared it; it hasn’t come back maybe because it hasn’t left the garage since I don’t know. Any help would be greatly appreciated.

I am thinking a vacuum leak or faulty MAF Sensor.

Mass Airflow Sensor Handling Notice

  • Handle the MAF sensor carefully.
  • Do not drop the MAF sensor in order to prevent damage to the MAF sensor.
  • Do not damage the screen located on the air inlet end of the MAF.
  • Also Do not touch the sensing elements.
  • Do not allow solvents and lubricants to come in contact with the sensing elements.
  • Use a small amount of a soap based solution in order to aid in the installation.

2002 Chevy Camaro wont go into park

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Jan 302020

Chevy Camaro

I have a 2002 Chevy Camaro. Today as I went to put it in park it wouldn’t go. So I pulled up the emergency brake for a few seconds and then released it. I was able to then put it in park. It did this a couple of times until I got home. Still wouldn’t go into park and this time pulling and releasing the emergency brake didn’t work like before. The only way to keep it in a parked position now is to keep the emergency brake up. What could be the problem and would it be an expensive thing to fix? I live on a small disability check so really can’t afford a big problem. Help!

This could be a number of things. I would start with making sure nothing is blocking the shifter. Sometimes coins, etc. block the shift mechanism from being able to move. Make sure the button on the shifter isn’t sticking. Also try putting the car in the air, taking the linkage off the transmission and see if you can get it in park by hand. If you can, then you know it’s in your shift cable/linkage. If you still can’t get it into park, then you know it’s inside the transmission. If the cable is stretched that sometimes can cause it. Maybe even get under the car while someone else moves the shifter to see what’s happening.

Shift Cable Adjustment

  1. Place transmission shift control lever into Park position and apply parking brake.
  2. Raise and support vehicle.
  3. Position transmission range selector lever to Park by rotating range selector lever clockwise until it reaches full mechanical stop position.
  4. Snap transmission shift cable into bracket with cable adjustment button up.
  5. Snap shift cable onto range selector lever pin, then press cable adjustment button down.
  6. Insert retainer to fitting of shift cable.
  7. Lower vehicle.

Won’t go into park

Chevy Code P1635 Chevy Lumina 2001

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Jan 272020


When I try to drive my 2001 Chevy Lumina I can floor it and it hardly goes. Then kicks in and does this back and to. I got error code p1635 . Also have replaced the fuel filter, fuel pump, map sensor, IAC controller still doing same thing.

Chevy Code P1635 – 5 Volt Reference Circuit

Circuit Description

The PCM uses the 5 Volt Reference A circuit as a sensor feed to the following sensors:

  • TP sensor
  • MAP sensor
  • EGR Valve Pintle Position sensor
  • Fuel Tank Pressure Sensor

The PCM monitors the voltage on the 5 Volt Reference A circuit. If the voltage is out of tolerance, the PCM will set DTC P1635.

Conditions for Running the DTC
The ignition is ON.

Conditions for Setting the DTC

  • The PCM detects a voltage out of tolerance condition on the 5 Volt Reference A circuit.
  • Above condition for longer than 10 seconds.

Action Taken When the DTC Sets

  • The PCM will illuminate the malfunction indicator lamp (MIL) during the second consecutive trip in which the diagnostic test has been run and failed.
  • The PCM will store conditions which were present when the DTC set as Freeze Frame/Failure Records data.

Conditions for Clearing the MIL/DTC

  • The PCM will turn OFF the malfunction indicator lamp (MIL) during the third consecutive trip in which the diagnostic has run and passed.
  • The history DTC will clear after 40 consecutive warm-up cycles have occurred without a malfunction.
  • The DTC can be cleared by using a scan tool.

Diagnostic Aids
Inspect for the following conditions:
Many situations may lead to an intermittent condition. Perform each inspection or test as directed.

Remove any debris from the connector surfaces before servicing a component. Inspect the connector gaskets when diagnosing or replacing a component. Ensure that the gaskets are installed correctly. The gaskets prevent contaminate intrusion.

  • Loose terminal connection
  • Use a corresponding mating terminal to test for proper tension. Refer to Testing for Intermittent Conditions and Poor Connections , and to Connector Repairs in Wiring Systems for diagnosis and repair.
  • Inspect the harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, and faulty terminal to wire connection. Refer to Testing for Intermittent Conditions and Poor Connections , and to Connector Repairs in Wiring Systems for diagnosis and repair.
  • Damaged harness—Inspect the wiring harness for damage. If the harness inspection does not reveal a problem, observe the display on the scan tool while moving connectors and wiring harnesses related to the sensor. A change in the scan tool display may indicate the location of the fault. Refer to Wiring Repairs in Wiring Systems for diagnosis and repair.
  • Inspect the powertrain control module (PCM) and the engine grounds for clean and secure connections. Refer to Wiring Repairs in Wiring Systems for diagnosis and repair.

If the condition is determined to be intermittent, reviewing the Snapshot or Freeze Frame/Failure Records may be useful in determining when the DTC or condition was identified.

Test Description
The numbers below refer to the step numbers on the diagnostic table.

DTC must have failed this ignition to be properly diagnosed.

The 5 Volt Reference circuits have multiple PCM pins, be sure to test all components on the 5 Volt Reference A circuits only.

3. The 5 Volt Reference circuits have multiple PCM pins, be sure to test all components on the 5 Volt Reference A circuits only.

9. This vehicle is equipped with a PCM which utilizes an Electrically Erasable Programmable Read Only Memory (EEPROM). When the PCM is being replaced, the new PCM must be programmed.

DTC P1635 5 Volt Reference Circuit


Step Action Value(s) Yes No



Did you perform the Powertrain On–Board Diagnostic (OBD) System Check ?



Go to Step 2


Go to Powertrain On Board Diagnostic (OBD) System Check



  • Turn ON the ignition , Engine OFF.

  • With a DMM, Measure the voltage from the 5 Volt Reference circuit to a good ground.

Does the voltage measure near the specified value?


5.0 V


Go to Step 5


Go to Step 3




With a DMM observe the voltage while disconnecting all components connected to the 5 Volt Reference circuit one at a time.

Does voltage change when one of the components is disconnected?



Go to Step 8


Go to Step 4




Does the voltage measure less than the specified value?


4.9 V


Go to Step 6


Go to Step 7



  1. Reconnect the component tested earlier.

  2. Test another 5 Volt Reference circuit to a good ground.

Does the voltage measure near the specified value?


5.0 V


Go to Step 9


Go to step 8




Test all 5 Volt Reference A circuits for a short to ground. Refer to Wiring Repairs in Wiring Systems.

Did you find and correct the condition?



Go to Step 10


Go to Step 9




Test all 5 Volt reference A circuit for a short to voltage. Refer Wiring Repairs in Wiring Systems,

Did you find and correct the condition?



Go to Step 10


Go to Step 9




Replace the affected component. Refer to appropriate component replacement.

Did you complete the replacement?



Go to Step 10





Replace PCM. Refer to Powertrain Control Module Replacement/Programming.

Did you complete the replacement?



Go to Step 10





Use the scan tool in order to clear the DTCs

Operate the Vehicle within the conditions for running the DTC as specified in the supporting text .

Does the DTC reset ?



Go to Step 2


System OK




Shudder 2016 Chevrolet Traverse AWD TSB 16-NA-175

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Jan 242020


Transmission seems to “stutter” at 20-25 ph and 40-45 ph

If I had to guess I would say that the transmission was serviced with the wrong type of transmission fluid. They do sell a corrective additive called Shudder Fix. However the better course of action would be to have the transmission fluid replaced with the correct type. There is a TSB – Technical Service Bulletin out on this issue.

TSB# 16-NA-175

TSB 16-NA-175 Description

Shake and/or shudder during light acceleration between 25 and 80 MPH at a steady state. (June5, 2018)


Some customers may comment on any of the following conditions:

  • A shake and or shudder during light acceleration between 25 and 80 mph steady state driving when transmission is not actively shifting gears.
  • A shudder feeling that may be described as driving over rumble strips or rough pavement.
  • Shudder feeling is evident in both Drive and M7 MY15-16 &L7 MY17 and MY18 Mode.
Diagnosis Instructions

To ensure TCC Shudder is diagnosed correctly, please drive the following schedule on a smooth road with transmission sump temperature between
122°F (50°C) – 158°F (70°C).
Important: For some road conditions, it may be required to apply the brake pedal and throttle simultaneously to stay within desired gear, engine
firing mode, engine torque range, and engine/vehicle speed ranges.

For Full Size Trucks/SUVs– Press and hold the tow-haul mode button for 5 seconds to disable grade braking to prevent downshifts during test.

Run the following tests for 3 operational modes:
A. Normal Operation (GDS2 for viewing only).
B. GDS2 Commanding TCC in Disabled Operation. (TCC Open).
C. GDS2 Commanding TCC in Enabled Operation. (TCC Locked).

To confirm TCC Shudder, the vibration concern must be created in normal operation (Mode A) of the test.

If the concern is gone with the torque converter clutch disabled (Mode B, TCC Open) and is gone with torque converter clutch enabled (Mode C, TCC Locked), then the vibration root cause is TCC Shudder, and the fluid flush procedure corrective action described below should be performed.
If the concern is not present in Mode A, then the vibration concern is NOT TCC shudder.

If the concern is still present with the torque converter clutch disabled (Mode B) or with the torque converter clutch enabled (Mode C, TCC slip speed at zero), then the vibration root cause is NOT TCC Shudder.
Vibrations not identified as TCC Shudder should be further investigated using the Vehicle Vibration Diagnosis in SI as a starting point.

Service Procedure

Requires Mobil 1 Synthetic LV ATF DEXRON HP transmission fluid.
Note: U.S. dealers must order the Mobil 1 Synthetic LV ATF DEXRON HP
fluid through your local General Motors oil distributor. When contacting
the General Motors oil distributor request Mobil 1 Synthetic LV ATF DEXRON HP.
Canadian dealers must order part number 19355657 through Kem Krest Canada.
1. Drain, Clean pan/magnet, Replace Filter, Oil Fill, & Remove fluid from the oil cooler lines.
◦ A.) Use filtered compressed air regulated to 60 psi to remove transmission fluid from the transmission oil cooler lines.
◦ B.) Remove the transmission fluid pan and drain transmission fluid following SI procedures for the application you’re working on. Discard
all oil.
Note: If you find that the fluid is cloudy, milky, or appears to be contaminated with water or engine coolant, DO NOT proceed with below steps. Follow Both SI Procedures for “Cooling System Leak Testing” and “Engine Coolant/Water in Transmission.”
◦ C.) Clean the pan/magnet if any metallic particles present and replace transmission filter.

Install the transmission fluid pan and refill with new Mobil 1 Synthetic LV ATF DEXRON HP transmission fluid following the Fluid Fill Procedure in SI
to obtain correct fluid level. The shudder should be improved after the completionof this flush procedure.
Note: Shudder should improve directionally right away, but for full affect, the vehicle may need to be driven up to 200 miles (322 km) and a minimum of two cold to hot drive cycles before determining if the fluid flush corrected the condition or not. Do not re-evaluate vehicle for additional customer shudder concerns until the vehicle has been driven 200 miles (322 km).