May 092016

1998 Chevy Astro Starter ProblemThe battery has a full charge and plenty of gas and it wont start could it be the starter?


Of course it could be if the engine is not turning over at all. But testing the starting system first may be the best course of action.

  • Check for good battery negative at starter case
  • Have someone hold the ignition key in the “START” position
  • Check for Battery Positive at the “S” terminal on the starter, if seen replace starter. If not seen, check the starter relay and neutral switch. Then trace wiring in the wiring-harness.

1998 Chevy Astro Van Starter Wiring Diagram


Starting System Operation

Voltage is applied at all times to the Ignition Switch from Fuse 6 through the RED (242) wire. When the Ignition Switch is turned to the Start position, voltage is then applied to the CRANK fuse through the YEL (5) wire. From the CRANK fuse, voltage is applied to the Park Neutral Position and Backup Lamp Switch through the PPL (806) wire. When the Park Neutral Position and Backup Lamp Switch is placed in Park or Neutral, voltage is then applied to the coil of the Starter Relay through the YEL (1737) wire. Since the Starter Relay is permanently grounded at G104 through the BLK (850) wire, the relay will energize.

Voltage is applied at all times to the  Relay contacts from Fuse 6 through the RED (242) wire. When the Relay energizes, the relay contacts close, and voltage is then applied to the Starter Solenoid. Since the  Solenoid is permanently case grounded, the Solenoid will energize two coils. The Pull-in Winding coil will energize to pull the  Solenoid contacts closed. When the contacts close, a plunger on the contacts will cause the Pull-in Winding coil circuit to open. Then the Hold-in Winding coil will hold the Solenoid contacts closed. Voltage is then applied to the Starter Motor from the Battery through the BLK (1) wire and closed contacts of the  Solenoid. Since the  Motor is also permanently case grounded, the motor will run until the Ignition Switch is moved out of Start position. When this happens, a spring in the  Solenoid will move the  Solenoid contacts and the plunger back to the rest position.



May 092016

2000 Chevy ExpressCheck codes are misfire. cylinders 5 and 7 show solid misfires. changed wires, plugs, fuel pressure reg, and injection spider. still misfires. plugs show good spark. compression good. block check good.


The Code P0300 means that a cylinder(s) is misfiring or is randomly misfiring. Start by checking for intake leaks, intake gaskets are common caused of multi-cylinder misfiring. If no leak are found the next step is to replace the spark plugs. If the problem persist more tests needs to be done to diagnose problem, see “Possible Causes”.

Possible causes
– Faulty spark plug (s)
– Faulty ignition coil (s)
– Clogged or faulty fuel injector (s)
– Intake air leak
– Fuel injectors harness is open or shorted
– Fuel Injectors circuit poor electrical connection
– Ignition coils harness is open or shorted
– Ignition coils circuit poor electrical connection
– Insufficient cylinders compression
– Incorrect fuel pressure

When a misfire occurs, engine speed will fluctuate. If the engine speed fluctuates enough to cause the Crankshaft Position (CKP) sensor signal to vary, the Engine Control Module (ECM) can determine that a misfire is occurring.

May 062016

Started the truck a few weeks ago started fine then the next day went to start it and it was sluggish but when i shut if off it just clicked. So i assumed it was the starter just got the time to swipe it out today approximately three weeks since the starter assumption but after changing same results today all gauges are worming tested the batteries glow plugs are cycling and the indicator light comes one seem i have good voltage but the voltage meter is not showing it and when u start the truck it just clicks with no indication that it will crank at a loss considering it took 4 hours to to get the old starter off in the freezing cold today Really needing some suggestions as we are getting snow and more coming it my winter work vehicle. Thanks in advance for any help or advice someone could lend


Replace the battery.


It takes very little to illuminate lights and activate glow plugs. The starter however requires the most juice to turn over the engine. The battery may read 12 volts setting still without load. When you load test it (draw amperage) the voltage will drop below usable condition.

I use a Battery Load Tester to check my batteries.

Apr 282016

2003-chevy-silveradoWhy would my ABS Brake light come on and my speedometer start jumping when I’m in 2wheel drive and hit 30-40mph. And doesn’t do it in 4wheel hi or low?


The most common reason for the ABS Brake light to come on is when the brake fluid level is low. Since the brake fluid level moves around it may come on while moving up or down hills or on heavy acceleration or deceleration. As for the Speedometer jumping around, it is possibly a VSS- Vehicle Speed Sensor issue or a malfunction in the gauge cluster assembly. Gauge cluster issues are also common on these Chevy trucks

Apr 212016

2000 Chevy SilveradoI changed oil pan, timing cover and water pump gaskets on my 2000 Chevy Silverado 1500 2wd 4.3l v6. Leaked oil. it ran fine before I did this and when I got done it would crank but not start. code p0336 came up, changed the crank sensor still no start, did a battery cable relearn and still no start. I did mess up pulling the balancer and pull the rubber about 1/2 inch off on one side, pressed it back on and it looks fine, but could that cause a no start? so far I’ve changed cap , rotor and wires. tried putting old crank sensor back in and still nothing. keeps giving me a p0336 code. wires and plug on sensor look good. had coil and icm tested, they’re good. don’t know what it could be now other than the balancer. any advice?


I would lean toward the wiring harness, the connection or the signal plate.

Signal Plate

Code P0336

– Crankshaft Position Sensor ‘A’ Circuit Range/Performance

code P0336Possible causes

  • Faulty crankshaft position sensor
  • Crankshaft position sensor wiring harness is open or shorted
  • Crankshaft position sensor circuit poor electrical connection
  • Signal plate may be damaged
  • Starter motor may be faulty
  • Starting system circuit
  • Dead or weak battery

The Crankshaft Position Sensor (CKP) also known as the crank position sensor is an electronic device used in an engine to record the rate at which the crankshaft is spinning. This information is used by the Powertrain Control Module (PCM) to control ignition and fuel injection. The sensor system consists of a rotating part, typically a disc, as well as a static part, the actual sensor.

When the engine is running, the high and low parts of the teeth cause the gap with the sensor to change. The changing gap causes the magnetic field near the sensor to change. The change in the magnetic field cause the voltage from the sensor to change.

Apr 192016

2005 Chevy TrailblazerMy 2005 Chevy Trailblazer 2WD won’t accelerate beyond 25-30 mph, transmission fluid was replaced/flushed. I’m taking it to a shop today, any suggestions? thanks


It can be tough when trying to diagnose your Chevy Trailblazer for lack of acceleration. When it won’t accelerate normally there are a few things that might cause this. If the check engine light is on the first step would be to pull the engine trouble codes. If the engine seems to rev high and your Trailblazer doesn’t want to move at the same time, the most likely reason would be low on transmission fluid. Check the fluid level first. If the level is low, top it off and resume testing. If the transmission fluid level is full, take note to the color. If it is burnt looking or dark, this would indicate burnt internal clutches. Rebuild the transmission to fix it. If the color still looks new, and internal valve body or solenoid issue is most likely the cause.

Apr 182016

2004-chevy-silveradoEvery couple of days if i let my 2004 Chevy Silverado 1500 sit the battery drains. I have to jump it to start it but every time I take it and have it tested they can never find anything wrong. Battery cables are good and tight and have changed the battery and alternator and shut off the interior lights to where they don’t come on is there anything else i should be looking at


Glove box bulb is one place to look. Wait till night time and then look as it will be easier to see a light. Also check for loose change in the cigar lighter and power ports. A dime or gum wrapper is all it takes to get lodged in there and it will drain the battery.

You may disconnect the battery and see if the battery is still dead after it sits. In most cases the battery itself is the problem. It may test OK at the local parts house, but I can assure you the test is not that accurate.

If you still are having issues at this point you may has a parasitic draw.

Wiki has done a great job on explaining how to test for a parasitic battery draw.

Apr 152016

2003 Chevy Malibu
I’m having problems with my power windows. I replaced the power window switch on driver side door, it worked great for about a week, tonight after it got really cold and snowing it decided that when I backed into my driveway the window on driver door started going down on its own. It will go back up when I push button but when I release switch it goes down. Every time the key is turned it goes down. All other windows work fine. Any clue why this started and how to fix it?


Three reasons come to mind right off that would cause the power window to go down on its own. One would be the new part has an internal flaw. I would however exclude that if this is the reason you replaced the power window switch in the first place. The second reason would also be the most common. The act of opening and closing the door over a period of time takes a toll on the wiring harness that runs through the door jam. These wires become brittle and crack and break. When this happens, the wires can sometimes touch one another causing some weird things to happen. If you have the old switch, swap it out and see what happens. Then perform the “wiggle test” on the wiring if there was no change after swapping out the power window switch assembly.

Power WindowsThe third reason may have to do with the “AUTO” feature for the drivers side power window. This too is built into the drivers side power windows switch assembly.

Auto Power Windows

 The driver’s window also has an express-down feature. This switch is labeled AUTO. Press the rear of the switch partway, and the driver’s window will open a small amount. If the rear of the switch is pressed all the way down, the window will go all the way down.

To stop the window while it is lowering, press the front of the switch. To raise the window, press and hold the front of the switch.

2003 Chevy Malibu Power Windows Wiring Diagram

Use this diagram to trace any wiring issues you may have involving the power windows circuit.

Mar 312016

2006 Chevy Silverado

I recently cut my tail/ turn signal light lines and fixed some wiring issues. Got them working properly. Now speedometer wont work abs & brake light on will not shift out of 1st gear in drive. I can only get 2nd if I change it manually. Already changed VSS at transfer case. HELP!!!


If the problem wasn’t there before you went to fixing on the wiring, that would be the first place to start. Undo everything you just did to see if it all starts working again like it did before you messed with it. Looking over the wiring diagrams I do not see any connection between the turn signal lights and the transmission.

The brake and ABS light on being on as a separate issue generally come on together for the same reason.

  1. Low on Brake fluid – How to check fluid levels
  2. Failed wheel speed sensor
  3. Failed Hub Bearing – this takes out the internal speed sensor

I currently own a 2006 Chevy 1500 Z71 and have had to replace both front hub bearing assemblies prior to 60,000 miles. This is a common failure part. Here is the correct part to fit your vehicle, I have double checked for 4WD application. This is the New Style Series by Timken(top of the line) and should last longer. For less than $120.00 with free shipping. And yes the failed speed sensors or faulty signal from one of them will cause the transmission to shift erratically.
Follow image for more Details…

Mar 282016

Chevy Aveo
My Chevy Aveo is having a random cylinder misfire and wanted to know what the fuel rail pressure should be at idle.


With the ignition key in the “ON” position and the fuel pump relay jumped or activated with a scantool, the fuel pressure should read between 55 – 62 psi.

Chevy Aveo Fuel System Description

When the ignition is turned ON, the Engine Control Module (ECM) supplies power to the in-tank fuel pump, by energizing the fuel pump relay. The in-tank fuel pump remains ON as long as the engine is cranking or running and the ECM receives crankshaft reference pulses. If there are no reference pulses, the ECM turns the in-tank fuel pump OFF, 2 seconds after the ignition switch is turned ON or 2 seconds after the engine stops running.