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.

Mar 242016

4 wheel drive actuator chevy colorado 2004
was changing out my 4 wheel drive actuator Chevy Colorado when it cracked and left half of it in, how can I get the rest of it out so I can put the new one in


The Chevy Colorado 4 Wheel Drive actuator sticks in quite a ways. Having it break off is not normal and will require special care. First try to use channel locks to loosen any part that may still be sticking out. If nothing is left sticking out, then use a chisel and hammer it around. You may need to apply some heat to the area. Worse case you will need to replace the housing.

Mar 232016

blower motor resistor

Blower Motor Resistor

My 2001 Chevrolet Silverado 1500 has no power to the blower motor resistor. I have changed all the fuses under-hood and inside fuse panel still no power to my resistor..too the resistor harness off and found it is not connected to any wires at all. It just has one end for the blower motor resistor and the other end goes to the rear air that my truck is not equipped with there for no constant hot wire..I need help I can provide a pic if needed

Not sure exactly what wires you are looking at under the dash. The wiring colors should help to determine which one needs to go where. I have added the blower motor wiring diagram below. Make sure your battery is in good working order and the ignition key is in the “ON” position. You should see Battery positive at all times on the Orange wire going to Pin G on the resistor assembly. Then when the key is on and the blower motor is turned on to High you should see battery voltage on the other Orange wire at Pin F.

Blower Motor Resistor Symptoms

  • Fan only blows on low speed
  • Fan only blows on medium speed
  • Fan only blows on high speed
  • Fan does not blow air out the dash

Blower Motor Resistor Location

Looking at the image above you can see the resistor is located next to the motor. The entire assembly is accessible from under the dash below the glove box area. Removal of the sound deadening material may be necessary.
Quick test for a resistor going out. If the blower motor blows air on high but not on other speeds, replace the blower motor resistor. If it does not blow on any speeds, Check and confirm voltage to the fuses. Apply power direct to the blower motor for testing. If the blower motor works, and fuses are good, replace the resistor.

Mar 062016

2003 Chevy SilveradoI have a 2003 Chevy Silverado  with dual manual temperature controls issues. Drivers side temp control stays on blowing hot air. Passenger side controller works fine. Checked the actuator on the right side above the hump on the floor works fine. which one is it. Even switching to A/C it blows hot air while passenger blows cold.


The drivers side air temperature actuator which is considered the left side.

Air Temperature Actuator Replacement – Left Side

  1. Remove the center console, if equipped
  2. Remove the Instrument Panel
  3. Disconnect the electrical connector from the left air temperature actuator
  4. Remove the screws from the left air temperature actuator
  5. Remove the left air temperature actuator from the HVAC Module assembly

Installation – Install in reverse order

Air Temperature Controls Diagram 2003 Chevy Silverado

temperature controls 2003 Chevy Silverado


Mar 012016

Chevy Colorado

Keyless Entry

Do all 2011 Colorado crew cabs come with the remote keyless entry wiring or only the ones with the remotes. I just bought this Colorado and it does not have keyless fobs and I would like to have remote do0r lock function to work but am not sure if wiring is installed.

The keyless entry system

The keyless entry system is a vehicle entry device. The keyless entry system is used in conjunction with the door locks to unlock the vehicle. Keyless entry will lock/unlock the doors when a corresponding button on the keyless entry transmitter is pressed. This is accomplished by the transmitter sending a radio frequency to the body control module (BCM). The BCM interprets the signal and activates the requested function. A low transmitter or vehicle battery or radio frequency (RF) interference from aftermarket devices, such as 2-way radios, power inverters, computers, etc., may cause a system malfunction. High RF traffic areas may also cause interference that could lead to a malfunction. Keyless entry allows you to operate the following components:

  • Door locks
  • Vehicle locator/panic alarm
  • Illuminated entry lamps

The keyless entry system has the following components:

  • Keyless entry transmitters
  • BCM
  • RF antenna
Keyless Entry Transmitters

The keyless entry transmitters are used to lock and unlock the vehicle door while away from the immediate are of the vehicle. Transmitters will operate at a distance of up to 20 m (65 feet), except Japanese and South Korean vehicles, which are limited to 4 m (13 feet). Up to 4 transmitters may be programmed to a single vehicle.

Body Control Module (BCM)

The BCM is a multifunction module that operates both the keyless entry system. When an RF message is received from a keyless entry transmitter, the BCM interprets this signal performs the specific function, i.e. door lock, door unlock, or vehicle locate.

RF Antenna

The RF antenna receives RF signals from the keyless entry transmitters and tire pressure monitor sensors. The antenna is basically a length of coax wire with the outer shield casing partially removed that is connected directly to the BCM.

Unlock Driver Door Only

Momentarily press the transmitter UNLOCK button in order to perform the following functions:

  • Unlock only the driver door
  • Illuminate the interior lamps for a determined length of time, or until the ignition is turned ON
  • Flash the exterior lights, if enabled through personalization
  • Disarm the content theft deterrent (CTD) system, if equipped
  • Deactivate the CTD system when in the alarm mode
Unlock All Doors – Second Operation

Momentarily press the transmitter UNLOCK button a second time, within 5 seconds of the first press, to perform the following function:

Unlock the remaining doors.
Lock All Doors
Press the transmitter LOCK button to perform the following functions:
•Lock all vehicle doors
•Immediately turn OFF the interior lamps
•Flash the exterior lights, if enabled through personalization
•Chirp the horn, if enabled through personalization
•Arm the content theft deterrent (CTD) system, if equipped
Vehicle Locator/Panic Alarm
A single press of the panic button performs the following functions:
•Pulses the horn three times
•Flashes the parking lamps three times

A press and hold of the panic button performs the following functions:
•Illuminates the interior lamps
•Pulses the horn and flashes the parking lamps for 30 second or until the following conditions occur:
◦The panic button is pressed
◦The ignition switch is turned to the RUN position with a valid key
Rolling Code
The keyless entry system uses rolling code technology. Rolling code technology prevents anyone from recording the message sent from the transmitter and using the message in order to gain entry to the vehicle. The term “rolling code” refers to the way that the keyless entry system sends and receives the signals. The transmitter sends the signal in a different order each time. The transmitter and the BCM are synchronized to the appropriate order. If a programmed transmitter sends a signal that is not in the order that the BCM expects, then the transmitter is out of synchronization. This occurs after 256 presses of any transmitter button when it is out of range of the vehicle.
Automatic Synchronization
The keyless entry transmitters do not require a manual synchronization procedure. If needed, the transmitters automatically re-synchronize when any button on the transmitter is pressed within range of the vehicle. The transmitter will operate normally after the automatic synchronization.

Feb 222016

2009 Chevy Traverse
I have Code P0752 on my Chevrolet Traverse 2009 with transmission problems , fault codes P0752 , P0989 , P0877,
I want to replace the valve body with TCM & speed sensors.
My question: is reprogramming required after installation?

Yes, the new TCM requires reprogramming.

Code P0752 – 1-2 Shift Solenoid Valve Performance – No Second or Third Gear

Code P0752 Possible causes

– Low transmission fluid level
– Dirty transmission fluid
– Faulty 1-2 Shift Solenoid valve
– 1-2 Shift Solenoid valve harness or connectors
– 1-2 Shift Solenoid valve circuit is open or shorted

Code P0752 Description

The 1-2 shift solenoid (SS) valve controls the fluid flow acting on the 1-2 and 3-4 shift valves. The 1-2 SS valve is a normally-open exhaust valve that is used with the 2-3 SS valve, in order to allow four different shifting combinations.

Code P0752 is detected when

The P0752 code is detected when the gear required by the ECM does not match the actual gear when vehicle is driven.

Code P0752 Related symptoms

– Engine Light ON (or Service Engine Soon Warning Light)
– Transmission will not shift gears.

transmission temperature chart

P0989 – Transmission Fluid Pressure Sensor/Switch E Circuit Low
P0877 – Transmission Fluid Pressure Sensor/Switch D circuit Low

Feb 112016

TPS Code for 2009 Chevy Aveo
Has 78,000 miles. New coil pack, battery, plugs, air filter. Only when its cold it has rough idling when started. It throws a TPS code, we have cleaned it numerous times but its really done nothing. There are times I lose all power when driving and no response from gas pedal. Ive read this car has had a lot of similar issues. But I cant afford to play a guessing game.


Hopefully it is as simple as performing the relearn procedure after cleaning. Idle relearn below. If not you may be looking at replacing the entire unit. You can pick one up here for about $140 including shipping.

TPS Code Throttle Body 2009 Chevy Aveo

TPS Code

P0122 – Throttle Position Sensor 1 Circuit Low Voltage

TPS Code Symptoms

– Engine Light ON (or Service Engine Soon Warning Light)
– Rough idle
– Loss of power when driving

TPS Code Possible Causes

– Faulty throttle position sensor
– Throttle position sensor harness is open or shorted
– Throttle position sensor circuit poor electrical connection

Throttle Actuator Control (TAC) System Description

The throttle actuator control (TAC) system is used to improve emissions, fuel economy, and drive-ability. The TAC system eliminates the mechanical link between the accelerator pedal and the throttle plate. The TAC system eliminates the need for a cruise control module and idle air control motor. The following is a list of TAC system components:

• The accelerator pedal assembly includes the following components:

– The accelerator pedal
– The accelerator pedal position (APP) sensor 1
– The APP sensor 2

• The throttle body assembly includes the following components:

– The throttle position (TP) sensor 1
– The TP sensor 2
– The throttle actuator motor
– The throttle plate

• The engine control module (ECM)

The ECM monitors the driver demand for acceleration with 2 APP sensors. The APP sensor 1 signal voltage range is from about 0.5-4.5 volts as the accelerator pedal is moved from the rest pedal position to the full pedal travel position. The APP sensor 2 range is from about 0.3-2.2 volts as the accelerator pedal is moved from the rest pedal position to the full pedal travel position. The ECM processes this information along with other sensor inputs to command the throttle plate to a certain position.

The throttle plate is controlled with a direct current motor called a throttle actuator control motor. The ECM can move this motor in the forward or reverse direction by controlling battery voltage and/or ground to 2 internal drivers. The throttle plate is held at a 5.7 degree rest position or the un-powered position using a constant force return spring. This spring holds the throttle plate to the rest position when there is no current flowing to the actuator motor.

The ECM monitors the throttle plate angle with 2 Throttle Position Sensors. The TP sensor 1 signal voltage range is from about 0.95-4.35 volts as the throttle plate is moved from idle to wide open throttle (WOT) position. The TP sensor 2 voltage range is from about 4.05-0.65 volts as the throttle plate is moved from idle to WOT position.

The ECM performs diagnostics that monitor the voltage levels of both APP sensors, both TP sensors, and the TAC motor circuit. It also monitors the spring return rate of the return springs that are housed internal to the throttle body assembly. These diagnostics are performed at different times based on whether the engine is running, not running, or whether the ECM is currently in a throttle body relearn procedure.

Every time the ignition cycle is cycled OFF, the ECM performs a quick throttle return spring test to make sure the throttle plate can return to the 7 percent rest position from the 0 percent position. This is to ensure that the throttle plate can be brought to the rest position in case of an actuator motor circuit failure. Observe, under cold conditions, the ECM commands the throttle plate to 0 percent with the ignition ON and the engine OFF to release any ice that may have formed on the throttle plate.

Throttle Body Relearn Procedure

The engine control module (ECM) stores values that include the lowest possible throttle position (TP) sensor positions and the rest positions. These values will only be erased or overwritten if the ECM is reprogrammed or if a throttle body relearn procedure is performed. Observe, if the battery is disconnected, the ECM will immediately perform a throttle body relearn procedure when the ignition is turned ON.

The ECM performs a relearn procedure twice and compares the results. If the results are nearly the same, the values are stored and the learn procedure is complete. The following is when the ECM performs a learn procedure:

• The ignition is ON.
• The engine is cranking.
• Deceleration
• The ignition is cycled OFF.

The ECM performs the learn procedure every 15 ignition cycles.

The ECM commands the throttle plate from the rest position to full closed, then stores TP sensor 1 and 2 voltages. This procedure takes less than 1 second. If any faults occur in the throttle actuator control (TAC) system, a DTC sets.

TAC System Default Actions/Reduce Power Modes

There are 4 reduce power modes that the engine control module (ECM) can default to if an error is detected in the throttle actuator control (TAC) system. The ECM monitors for the following conditions:

• Accelerator pedal position (APP) sensor 1 or 2 circuit fault
• APP sensor correlation fault
• A 5-volt reference circuit fault
• Battery voltage is less than 8 volts or greater than 24 volts.

If the ECM detects any of the above conditions, the ECM enters a Limited Performance reduced power mode. In the Limited Performance mode, the engine torque is limited. The ECM remains in this reduced power mode during the entire ignition cycle even if the fault is corrected. Usually accompanied with a TPS Code.

If there is no APP sensor information, the system enters a Forced Idle reduced power mode. In the Forced Idle mode, the ECM uses a default APP sensor position that is calculated from the brake switch, transmission gear position, and vehicle speed. The vehicle can be driven up to 32 km/h (20 mph) in this mode be engaging the transmission into gear and releasing the brake pedal.

If there is a condition with the TAC circuits, throttle actuator command vs actual position fault, or a TP sensor 1 or 2 circuit fault, the ECM enters a Power Manage reduced engine power mode. In the Power Manage mode, the throttle plate is not controlled. The engine torque is controlled to the desired value using cylinder shutoff and spark retard. The engine will idle or cruise with 2 cylinders enabled and accelerate with all 4 cylinders. Usually accompanied with a TPS Code.

If the ECM detects a severe failure in the TAC system, the ECM enters a Forced Shutdown mode. In this mode, the ECM disables the TAC system, the fuel system, and the ignition system so the engine will not start. The Forced Shutdown mode occurs when the ECM detects a severe internal ECM condition, the throttle plate is stuck open, or a large intake manifold vacuum leak is detected. Usually accompanied with a TPS Code.

Idle Relearn

When do I need to relearn the idle

The Idle Learn Procedure listed below must be performed whenever the following occurs:

• The throttle body assembly is replaced
• The throttle body is cleaned
• The engine control module (ECM) is replaced
• The idle air control valve (IAC) is replaced
• Power disconnection (battery cable, ECM fuse, etc.) (Delphi ECM only)

Idle Relearn Procedure

•Turn the ignition ON.
•Turn the ignition OFF for 15 seconds.
•Turn the ignition ON for 5 seconds.
•Turn the ignition OFF for 15 seconds.
•Start the engine in park/neutral.
•Allow the engine to run until the engine coolant temperature is greater than 85°C (185°F).
•Turn the A/C ON for 10 seconds, if equipped.
•If the vehicle is equipped with an automatic transaxle, apply the parking brake. While pressing the brake pedal, place the transaxle in drive (D) for 10 seconds.
•Turn the A/C OFF for 10 seconds, if equipped.
•If the vehicle is equipped with an automatic transaxle, while pressing the brake pedal, place the transaxle in park/neutral.
•Turn the ignition OFF. The idle learn procedure is complete.