Did not pass state inspection (vehicle)

This code does indicate a bad thermostat. Are there any other codes?

MIL is your malfunction indicator lamp, (check engine light)

CMD is the computer interface port, or OBDII port indicating a malfunction communicating with your cars computer

check all the fuses, primarily any marked pcm and retest your vehicle
note: your check engine or MIL has to be on in KOEO state (key on engine off), if the bulb is burned out everything will still work and the OBDII test computer will show MIL status ON, and if you don't have a computer to tell you that, you must get that light to light in the koeo state.

First step is to have the code or codes read.If the "check engine light" is on there will be a reason and should be a code or codes to be read.Once you have the codes,you can determine the correction needed to get that "check engine light" out and a valid emissions test completed.Get back to us with the codes found.

A code P0300 may mean that one or more of the following has happened:

• Faulty spark plugs or wires
• Faulty coil (pack)
• Faulty oxygen sensor(s)
• Faulty fuel injector(s)
• Burned exhaust valve
• Faulty catalytic converter(s)
• Stuck/blocked EGR valve / passages
• Faulty camshaft position sensor
• Defective compute
• P1105MAP/BARO Pressure Switch Solenoid Valve
• Check and clean the MAP sensor, or replace.
• P1492EVAP Canister Purge Control/Solenoid Valve (Circuit)
• Replacing the purge solenoid will clear code P1492 This should also clear code P0300 as well.
  

not a chevy expert, but if it goes into Failure Mode Strategy, that is difficult to diagnose, but usually an easy fix when you find it. The engine module very seldom is the cause.

here is what Ford book says:

On Board Diagnostics II System Overview The California Air Resources Board (CARB) began regulation of On Board Diagnostics (OBD) for vehicles sold in California beginning with the 1988 model year. The first phase, OBDI, required monitoring of the fuel metering system, exhaust gas recirculation (EGR) system, and additional emission related components. The malfunction indicator lamp (MIL) was required to light and alert the driver of the malfunction and the need for service of the emission control system. The MIL must be labeled "CHECK ENGINE" or "SERVICE ENGINE SOON." Associated with the MIL was a fault code or diagnostic trouble code (DTC) identifying the specific area of the fault.
The OBD system was proposed by the CARB to improve air quality by identifying vehicles exceeding emission standards. Passage of the federal Clean Air Act Amendments in 1990 has also prompted the Environmental Protection Agency (EPA) to develop on board diagnostic requirements. CARB OBD II regulations will be followed until 1999 when the federal regulations will be used.
The OBD II system meets government regulations by monitoring the emission control system. When a system or component exceeds emission thresholds or a component operates outside of tolerance, a DTC will be stored and the MIL will be illuminated.
Fault detection strategy and MIL operation are associated with trips and drive cycles. Each monitor has requirements for setting and clearing DTCs and for controlling the MIL. These processes, DTC and MIL operation, descriptions of the monitors and the definition of trip and drive cycles are discussed in detail within this section.
The diagnostic executive is the computer program in the powertrain control module (PCM) that coordinates the OBD II self-monitoring system. This program controls all the monitors and interactions, DTC and MIL operation, freeze frame data and scan tool interface.
Freeze frame data describes stored engine conditions, such as state of the engine, state of fuel control, spark, RPM, load, and warm-up status at the point the first malfunction is detected. Previously stored conditions will be replaced only if a fuel or misfire malfunction is detected. This data is accessible with the scan tool to assist in repairing the vehicle.
Powertrain Control Module The center of the OBD II system is a microprocessor called the powertrain control module (PCM). The PCM has a single 88 Pin connector. The PCM receives input from sensors and other electronic components (switches, relays, etc.). Based on information received and programmed into its memory (keep alive memory [KAM], etc.), the PCM generates output signals to control various relays, solenoids and actuators.
Keep Alive Memory (KAM) - The powertrain control module (PCM) stores information in keep alive memory (KAM), a memory integrated circuit, about vehicle operating conditions, and then uses this information to compensate for component variability. KAM remains powered when the vehicle ignition key is OFF so that this information is not lost.

Fail Safe - This system of special circuitry provides minimal engine operation should the powertrain control module (PCM), mainly the Central Processing Unit or EEPROM, stop functioning correctly. All modes of Self-Test are not functional at this time. Electronic hardware is in control of the system while in fail safe operation.


Component Control Fail Safe Condition Operation IAC1 Idle Air Held To Full Open. INJ 1
INJ 2
INJ 3
INJ 4
INJ 5
INJ 6 Fuel injection volume fixed according to driving conditions. Fuel is injected simultaneously into all cylinders once per crankshaft revolution. Timing for the injection is based upon the camshaft position sensor signal. EGR/EVAP* OFF EGR Valve and EVAP Canister Control Solenoid Closed. Ignition Timing Ignition Timing Fixed. HFAN ON High Fan Control Relay Energized. LFAN OFF Low Fan Control Relay Unenergized. ACR OFF A/C Relay Unenergized. MIL ON Malfunction Indicator Lamp On. FP ON Fuel Pump Control Relay Energized (Engine Running).
* Federal emissions
Adaptive Fuel Control Strategy The adaptive fuel control strategy is designed to compensate for variability in the fuel system components. If, during normal vehicle operation, the fuel system is detected to be biased rich or lean, the adaptive fuel control will make a corresponding shift in the fuel delivery calculation.
Whenever an injector or fuel pressure regulator is replaced, keep alive memory (KAM) should be cleared. This is necessary so the fuel strategy does not use the previously learned adaptive values.
To clear KAM, refer to PCM Reset in Section 2B , Diagnostic Methods.
Failure Mode Effects Management Failure mode effects management (FMEM) is an alternate system strategy in the powertrain control module (PCM) designed to maintain vehicle operation if one or more sensor inputs fail.
When a sensor input is perceived to be out-of-limits by the PCM, an alternative strategy is initiated. The PCM substitutes a fixed value and continues to monitor the incorrect sensor input. If the suspect sensor operates within limits, the PCM returns to the normal engine running strategy.

What does "not ready" mean?

A service technician will turn off the dashboard "check engine" light after most repairs. This resets the vehicle's emission system components to "not ready". The status remains "not ready" until the vehicle's computer has had adequate time to review the repaired component. This happens after the vehicle is driven for a period of time established by the manufacturer.

If the vehicle's emissions system status is "not ready" when it is presented at the E-Check station during the initial test cycle, a tailpipe emissions test may be conducted. If the vehicle is transferred to another test type, the vehicle must remain on the different test track until the vehicle passes the emissions test or receives a waiver. For example, if the vehicle undergoes an OBD II test and fails, it cannot be downgraded to a tailpipe test on a re-test; the vehicle must pass the OBD II test.

For initial and subsequent tests, if a dashboard light is on when the vehicle is presented at the E-Check station, the vehicle will fail the test.

How can the vehicle status be made ready?

When a vehicle is driven through its normal drive cycle, the computer reviews the emission control
system and if the vehicle was properly repaired, the system resets itself to ready. A normal drive
cycle includes operation at both cruising speeds and in stop-and-go traffic for up to a couple
weeks. This process should be followed before bringing the vehicle in to be tested.

A SCAN TOOL WILL TELL YOU WHAT CYLINDERS MISFIRING.THATS QUICK WAY TO CHECK.CHANGE FUEL FILTER AND CLEAN FUEL INJECTORS BY FILLING GAS TANK AND PUTTING A BOTTLE SEA FOAM IN TANK.MISFIRING LACK OF POWER AND STUMBLING ON ACCELERATION MOST TIME CLOGGED FUEL INJECTORS WILL CAUSE THOSE PROBLEMS.

need more info. was this a state test it failed?

go here for villager expert help.

http://autos.groups.yahoo.com/group/villagerquest/

U0121 Communication error to ABS HU/CM