Info - Cobalt - PDI and Service Guide

This is a special bulletin to introduce the new Chevrolet Cobalt. The purpose of this bulletin is to make you familiar with the vehicle's features and describe the action that your Service Department will need to take to ensure that you are able to fully service this exciting new model.

The purpose of this section is to familiarize you with the technical aspects of the vehicle. It is important to know the Cobalt is NOT built from the same platform as the previous Cavalier/Sunfire. The Cobalt is a whole new vehicle much different than the Cavalier/Sunfire. Although it replaces the Cavalier/Sunfire in the market segment, that is the only similarity between the vehicles.

Powertrain

The Cobalt comes equipped with a 2.2L (L61) DOHC L4 engine -- VIN Code F. The L61 produces 145 hp and 155 lb/ft of torque. The Cobalt SS Supercharged Coupe is equipped with a supercharged 2.0L (LSJ) DOHC L4 engine -- VIN Code P. The LSJ produces 205 hp and 200 lb/ft of torque.

The L61 engine is matched with either a 4T45E automatic transmission or the Getrag 5-speed (RPO M86) manual transmission. The LSJ engine, found in the SS Supercharged coupe, is matched with the Saab 5-Speed (RPO MU3) manual transmission. Note, the final drive ratio for the MU3 is 4.05.

Suspension

The Cobalt rides on a MacPherson strut front suspension and a semi-independent, torsion beam rear suspension. Suspension tuning for each model, includes steering feel, spring rate and stabilizer bar diameter, is dialed in to provide distinct driving and handling characteristics. Two suspension settings are available:

Cobalt's strut-type front suspension is compact, yet provides long wheel travel, with 90 mm of compression travel and 87 mm of rebound, which enhances the overall ride and handling. Monotube shocks are used for a more precise road feel. L-shaped front control arms contain a forward pivot bushing, which transmits most of the cornering force, and a larger composite rear elastomeric bushing that allows orbital movement to minimize harshness from road surface impacts. The control arms are made from steel on the FE1 suspension and aluminum on the FE5 suspension.

A direct-acting front stabilizer bar connects to each strut for more accurate steering response, reduced body roll, and improved cornering agility. All front suspension components are mounted to a new, rigid cradle assembly comprised of four large hydroformed steel tubes and two side members that are integrally welded to the front and rear crossmembers. The cradle is mounted to the Cobalt's space frame at four widely spaced points.

Steel hubs/bearings are bolted directly to the axle for a more precise feel. A hydraulic rear suspension bushing is employed on the FE1 suspension to improve the ride and suppress road noise.

Electronic Power Steering (EPS)

The Cobalt features rack and pinion steering, with Electric Power Steering (EPS) that is calibrated to each separate tire combination. EPS has a variable ratio, which optimizes the steering effort for a variety of conditions. More assistance is applied for low-speed maneuvers such as parking, while the power assistance tapers off at highway speeds for a firmer, more direct feel. The advantages of EPS are:

Major components of the EPS system are the Power Steering Control Module (PSCM), a torque sensor and the Electronic Power Steering motor. The PSCM, torque sensor and motor are serviced ONLY as an assembly.

PSCM:

Important: It is not necessary to program the PSCM if replacement is required.

The PSCM determines the amount of steering assist needed based on the vehicle speed from the serial data circuit, the amount of torque applied to the steering column shaft by the driver (determined by the torque sensor) and calculated system temperature estimated from a combination of commanded motor voltage and current levels and input from a thermistor internal to the PSCM. The PSCM performs a self-diagnosis routine each time the ignition is started to determine the state of the EPS system. The EPS system features an "overload protection mode". Symptoms of this mode are a decrease in assist or no assist. The "overload protection mode" will occur in any of the following conditions:

Torque Sensor:

The torque sensor is the PSCM's main input for determining steering direction and the amount of assist needed. As the steering wheel is turned and torsional twist is applied to the steering column shaft's torsion bar, the notched edges of the detecting rings 1 and 2 change alignment with each other. This change in alignment affects the magnetic characteristics around the detecting coil, changing the impedance of the detecting coil circuit, which changes the circuit's signal voltage level.

Electronic Power Steering Motor:

The EPS motor is a 58 amp motor. The amount of assist is regulated by the PSCM. Motor current is based mainly on the steering torque input to the PSCM. Output torque of the motor is transferred through a worm shaft and reduction gear.

Brakes

Cobalt is standard with 10.7 inch (256 mm) vented front discs and large, rear drums for base, LS and LT models. The SS Supercharged has four-wheel disc brakes, with 11.6 inch (296 mm) vented front discs and 10.6 inch (270 mm ) solid rear discs. Four-channel ABS with dynamic rear proportioning is standard on LS, LT and SS Supercharged models. It is optional on the base model. The ABS system uses integrated dynamic rear proportioning for improved stability and more effective use of the rear brakes when the vehicle is loaded.

Wheels and Tires

Four sport-tuned wheel and tire combinations are available with Cobalt.

Electrical Architecture

The electrical architecture of the vehicle is GMLAN* and requires the use of a CANDi module to communicate with the Tech 2®. There are potentially 10 different modules that can be found on the Cobalt. SI Document  1528110 provides a list of modules, as well as links to schematics, repair instructions and programming and set-up information.

* Note: The SS Supercharged L61 PCM is Class 2 only.

Traction Control

The Cobalt is available with Traction Control. For the Base and LS vehicles, ETS (RPO NW7) is an option. The vehicle must have an automatic transmission and ABS in order to have the ETS option. The LT model comes standard with ETS (RPO NW7). The ETS system controls the engine speed (torque) only.

Battery/Charging System

The battery is located in the spare tire well, under the load floor in the trunk. The battery is a top-post design and should not be swapped with a side-post design found on other GM vehicles. Should it be necessary to jump-start the vehicle, use the remote positive terminal and negative terminal on the driver's side shock tower in the engine compartment.

The Cobalt is equipped with Electrical Power Management (EPM), which is designed to perform regulated voltage control (RVC) to improve battery state-of-charge (SOC), battery life, and fuel economy. The system is designed to monitor and control the charging system and send diagnostic messages to alert the driver of possible problems with the battery and generator. The system primarily utilizes existing on-board computer capability to maximize the effectiveness of the generator, to manage the load, improve battery SOC and life, and minimize the system's impact on fuel economy. The system performs 3 functions:

The battery's condition is estimated during key-off and during key-on. The SOC can be used as a diagnostic tool to tell the customer or the technician the condition of the battery. While running, the battery's degree of discharge is primarily determined by a battery current sensor, which is integrated to obtain net amp hours. The battery current sensor is a serviceable component that is connected to the negative battery cable at the battery. The battery current sensor monitors the battery current and directly inputs to the BCM.

Express Down Window

The driver's window has an express-down feature which allows the window to lower all the way without continuously pressing the switch. The switch is labeled AUTO. Press the front of the switch all the way down and release. To stop the window while it is lowering, pull up on the front of the switch momentarily.

DIC

To operate the DIC, the ignition switch must be in the "Run" position. The DIC is controlled through two buttons located on the instrument panel to the right of the steering wheel. The DIC messages will be shown on the instrument panel cluster display. Press the "i" (mode) button to scroll through the vehicle information. Press the "arrow" (set) button to select a mode option or to acknowledge a warning message. A variety of the vehicle's features can be personalized using the "i" (mode) and "arrow" (set) buttons. The features that may be personalized include:

Personalization Features:

To display/program the personalization features, simultaneously press and hold the "i" and "arrow" buttons. The personalization features will display on the DIC.

The purpose of this section is to familiarize you with some of the unique characteristics of the vehicle. The following functions may operate differently than what the customers are used to and are considered normal.

4T45E Automatic Transmission

Current gear selector indicators are: PRND21. The indicator label does not match the function (i.e. selecting range "2" will actually allow the transmission to shift up to third gear above 40 mph (64 km/h) and provides 2nd gear engine braking limited to below 40 mph (64 km/h)). Range "1" will allow the transmission to shift from 1st to 2nd gear (i.e. provides 2nd gear engine braking greater than 40 mph (64 km/h) and 1st gear braking below 40 mph (64 km/h)). The traction light will also illuminate if the transmission is put in 1st gear.

Lock Indicator

Customers may comment that the "lock" symbol located on the I/P will flash even when the vehicle is not locked. This is considered a normal condition. It is important to note that the theft system is not activated unless the vehicle's doors have been locked by either using the RKE or the door lock switch.

Automatic Headlamp Control

The Cobalt is equipped with an Automatic Lamp Control system which automatically turns the headlamps and other exterior lamps on at dusk or when necessary. The exterior lamps can also be operated manually. The I/P backlight is not integrated in the headlamp switch. The automatic lamp control system must determine if it's dark enough to turn I/P backlights on.

The Automatic Lamp Control system's light sensor is located on the top of the instrument panel. It is important to avoid placing any objects on or near the sensor, or covering up the sensor.

Important: In rainy weather, etc., the customer may comment that they manually turned on the headlamps; however, the I/P lights did not come one. It is important to note that the I/P backlight will only turn on when indicated by the Automatic Lamp Control's light sensor. This condition is not related to the headlamp switch function, BCM or I/P function. This is considered a normal condition and no parts should be replaced.

Rear Window Defogger

The button for the rear window defogger is the middle button located on the HVAC control head. The rear window defogger will remain activated for 20 minutes. After 20 minutes, the rear window defogger will turn off. You may continue to press the rear window defogger to activate for an additional 20 minutes.

Important:  The rear window defogger will not turn off after 20 minutes if the vehicle speed is continuously greater than 50 mph (80 km/h).

Remote Keyless Entry

A new Vehicle Locator feature has been added to the Remote Keyless Entry. The vehicle must be turned off to operate this feature. Press and hold the "horn" button on the fob for approximately one second to locate your vehicle. The horn will sound three times and the hazard lamps will flash three times. To sound the panic alarm, press and hold the button for three seconds. The horn will sound and the hazard lamps will flash for 30 seconds. Press the button again or turn the ignition key to any position to cancel the panic alarm.

Technician's should note, the RKE is non-functional if the vehicle speed is greater than 3 mph (5 km/h).

Ambient Temperature Gauge

The Cobalt is equipped with an ambient temperature gauge located in the DIC. Vehicle speed must be greater than 18 mph (29 km/h) for the gauge to take a new reading. This compensates for potential heat-soak situations, such as slow moving traffic, that can effect the accuracy of the gauge. Anytime the vehicle speed is less than 18 mph (29 km/h), the gauge will not reflect the current temperature.

Ignition Cylinders

A special tool is required to service the lock cylinder. Until such time the tool is available (estimated February 2005), it will be necessary to replace the lock cylinder.

Trunk Release

The trunk release button can be found inside the storage bin located on the lower left side of the I/P (between the steering wheel/column and driver's door).

Windshield Wiper Operation

There are three wiper modes: Pulse, Low and High. In the Pulse mode, it is important to note that the wiper timing will fluctuate with the vehicle speed. If the vehicle speed is less than 50 mph (80 km/h), the wipers will toggle anywhere between low and 3 seconds between wipes. In certain weather situations, if vehicle speed is less than 50 mph (80 km/h), the customer may find it necessary to switch the wipers to the Low mode.

Power Mirror (RPO DC8, if equipped)

The power outside rearview mirrors may be adjusted using the controls located on the door panel. It is important to press the control button at the 12 o'clock, 3 o'clock, 6 o'clock, or 9 o'clock position in order to move the mirrors. If the control button is pressed between these positions (arrows), the mirrors will not move.

Fuel Range Calculation

Important: Vehicle speed input is required to calculate the fuel range information. Therefore, the vehicle must be driven after re-fueling in order for the DIC to reflect the accurate fuel range information.

The fuel range information shown on the DIC is an estimated fuel range. Fuel range is estimated based on the current driving situation. The fuel gauge should be used to determine the actual fuel/distance remaining. Be sure to reset the fuel economy on the DIC before delivering the vehicle to the customer.

Accessory Power Outlets (APO)

The Cobalt is equipped with two APOs, both located on the console - one beneath the HVAC control head and the second located rearward of the shift selector. If the vehicle is equipped with a "smoker's package", the APO located below the HVAC control head has been converted to a cigarette lighter. It is recommended not to use this position as an APO. If the cigarette lighter is used as an APO, it could result in a blown fuse.

The following tools are essential to service the Cobalt:

Oil Life Monitoring System -- it is important to reset the remaining oil life (using the DIC) to 100% after each oil change. Refer to the Owner's Manual for more details.

Transmission Fluid Service -- the 4T45E is a sealed transmission and does not contain a dipstick. The transmission fluid requires 100,000 mile (160,000 km) service (under normal driving conditions). Consult the Owner's Manual for the exact maintenance schedule.

The 2005 Chevrolet Cobalt was featured in the October 2005 New Model Features IDL -- Course # 10280.22D (U.S.). Dealers in Canada should watch for a Service Know-How release..

The PDI form was revised for the 2005 model year to ensure special attention is paid to the following areas (refer to Corporate Bulletin Number 04-00-89-028):

* For Dealers in Canada, the revised PDI form for the 2005 model year is available for download from the "GM World of Warranty" on the GMinfoNET.