Top 20
2005 Chevrolet Cobalt Questions & Answers
Have a 2005 cobalt chevy code U2105 says something is not communicating? Where could the issue be
• DTC U2105 Lost Communications With Engine Control System
Modules connected to the GMLAN serial data circuits monitor for serial data communications, during normal vehicle operation. Operating information and commands are exchanged among the modules. The modules have programmed information about what messages are needed to be exchanged on the serial data circuits, for each virtual network. The messages are also supervised and some periodic messages are used by the receiver module as an availability indication of the transmitter module. The supervision time-out period is 250 ms. Each message contains the identification number of the transmitter module. When a message that indicates the availability of the transmitter module is not received, the receiver module sets a DTC 21xx where xx is equal to the 2-digit identification number of the transmitter module.
The DTC descriptors listed below provide a method for determining which module is not communicating. A module with a GMLAN serial data circuit malfunction or which loses power during the current ignition cycle will have a Loss of Communication DTC set by other modules that depend on information from that failed module. The modules that can communicate will set a DTC indicating the module that cannot communicate.
Your best bet , take it to a qualified repair shop .
2005 cobalt..back turn signals work, flashers work in the back, headlights work all around. Front flashers and turn signals come on, do not flash..help
Do you know anything about automotive electronic's ? BCM - body control modules ? DTC'S - diagnostic trouble codes ?
Turn Signal Lamps
The body control module (BCM) is responsible for controlling the turn signals and hazard lamps. When the turn signal switch is placed in either the left turn or right turn position, the BCM receives a signal from the turn signal switch. The BCM then sends an on-off voltage signal to either the left or right turn signals and their instrument panel cluster (IPC) indicator. When the hazard switch is pressed, the BCM receives a signal from the hazard switch. The BCM then will send an on-off voltage signal to all the turn signal lamps. All the turn signal lamps will flash including both IPC turn signal indicators.
Hooking up a professional type scan tool an checking for DTC'S in the BCM would be the first step in the diagnostic procedure .
How to change headlamp bulb on a 2005 chevy cobalt
Its hard to fit your hand in the small space so best to remove the 2 bolts on top 10mm that are holding the headlight in place. The from the side, pull/pop the headlight assembly forward and out from behind the front grill area. Once its out, you can easily turn the retaining collar and remove the bulb. Be sure not to touch the glass of the new bulb or the oils from your fingers will create a hotspot and shorten the bulb life. Replace in reverse order.
The reduced engine power light
The check engine light being on now is a different problem , Have DTC'S - diagnostic trouble codes checked ,will have something to do with electronic throttle control . That is what reduced engine power is about . It's in a reduced power mode.
Reduced Engine Power Mode
When the ECM detects a condition with the TAC system, the ECM may enter a reduced engine power mode. Reduced engine power may cause one or more of the following conditions:
• Acceleration limiting--The ECM will continue to use the accelerator pedal for throttle control; however, the vehicle acceleration is limited.
• Limited throttle mode--The ECM will continue to use the accelerator pedal for throttle control; however, the maximum throttle opening is limited.
• Throttle default mode--The ECM will turn off the throttle actuator motor and the throttle will return to the spring loaded default position.
• Forced idle mode--The ECM will perform the following actions:
- Limit engine speed to idle by positioning the throttle position, or by controlling the fuel and spark if the throttle is turned off.
- Ignore the accelerator pedal input.
• Engine shutdown mode--The ECM will disable fuel and de-energize the throttle actuator.
Do you know what electronic throttle control is ?
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Throttle Actuator Control (TAC) System Description
The throttle actuator control (TAC) system delivers improved throttle response and greater reliability and eliminates the need for mechanical cable. The TAC system performs the following functions:
• Accelerator pedal position sensing
• Throttle positioning to meet driver and engine demands
• Throttle position sensing
• Internal diagnostics
• Cruise control functions
• Manage TAC electrical power consumption
The TAC system includes the following components:
• The accelerator pedal position (APP) sensors
• The throttle body assembly
• The engine control module (ECM)
Your best bet , take it to a qualified repair shop .
Power steering goes out
General Motors has decided that a defect, which relates to motor vehicle safety, exists in certain 2005-2010 model year Chevrolet Cobalt vehicles;
2005 model year Pontiac Pursuit; 2005-2006 model year Pontiac G4; 2006 model year Pontiac G5 Pursuit; and 2007-2010 model year Pontiac G5
vehicles equipped with electric power steering. Some of these vehicles have a condition in which a sudden loss of power steering assist could occur at
any time while driving the vehicle. If the power steering assist is lost, a chime will sound and a "Power Steering" message will be displayed in the
Driver Information Center to inform the driver of the condition. Steering control will be maintained, as the vehicle defaults to a manual steering mode.
If power steering assist is lost, it may require greater driver effort at low vehicle speeds, for example, below 15 mph (25 km/h). Unless a driver
compensates for this additional effort, it may increase the risk of a crash.
My 2005 chevy cobalt will not stay at a constant idle
Well you shouldn't pay to much attention to what some people say . Never use carb. cleaner to clean a mass air flow sensor , they make a special cleaner for mass air flow sensors . And you just spray the sensor an let it air dry ,then put it back together . And as far as dealer's not being able to find this ,i'm sure some may not . Just as any independent repair shop may not . I have thrity years experience at GM dealerships ,started at a Chevy dealer back in 1984 ,right out of a two year automotive technician program . Have worked at Cadillac , pontiac , GMC etc.....
Listening to others making guesses as to what the problem is ,mite fix the problem an then again it may not . There are a lot of electronic componets on your vehicle that could cause your problem , looking at sensor data on a capable scan tool is the correct way to find your problem .
007 Idle Speed Problems Scan Data for Idle
The location of the fuel pump cut off switch on a 2005 Chevy Cobalt ?
There isn't one.
What testing have you done?
Make sure battery has a full charge. If it cranks good but won't start, have a helper crank it while you visually check for spark at the plugs. If spark everywhere, use a gage and check proper fuel pressure and fuel injector pulse. If your missing everything check for rpm signal. Any applicable trouble codes?
When you first turn on the key, no crank, can you hear the fuel pump run for a couple seconds? There is a fuel pump fuse in underhood fuse box.
I replaced the TCM in my 2005 Chevy colbolt, light come on but car won't start, turn key and anti theft icon comes on but doesn't stay on
TCM ? transmission control module ? Did you have it programmed ?
Reprogram the TCM. Refer to Control Module References for programming and setup information.
Transmission Control Module Programming and Setup
The transmission control module (TCM) must be programmed with the proper software/calibrations. Ensure that the following conditions exist in order to prepare for TCM programming:
• The battery is fully charged.
• The ignition switch is in the RUN position.
• The Techline equipment cable connection at the data link connector (DLC) is secure.
Program the TCM using the latest software matching the vehicle. Refer to up-to-date Techline equipment user instructions.
If the TCM fails to program, proceed as follows:
3.1. Ensure that the TCM connection is OK.
3.2. Inspect the Techline equipment for the latest software version.
3.3. Attempt to program the TCM. If the TCM still cannot be programmed properly, replace the TCM.
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