Stop/Start Disable, Inhibit, and Restart Reasons
WARNING: This page is about a different car, the 2016 Cadillac ATS. However, it is still accessible from the selected car via links, so may be relevant.
NOTE:
Not all parameters may be available in all vehicles
The following Autostop Disable parameters are only valid when Engine is Running. It indicated why are we currently inhibiting autostop at that moment in time.
Autostop Disable
| Scantool Parameter - Current Inhibit Reason | System State | Description | Expected Value | Recommended Check | Next Step |
|---|---|---|---|---|---|
| Autostop Disable Reason - Transmission Range | Engine Running | Transmission not in Drive | No | Ensure transmission is in drive. Stop/start will not function in manual mode. | If OK: Inform Customer - Normal Disable Condition If not OK: Refer to transmission diagnostics. |
| Autostop Disable Reason - Hood Ajar | Engine Running | Hood not latched | No | Ensure hood is closed and latched. | If OK: Refer to Hood Ajar Malfunction. If not OK: close hood. |
| Autostop Disable Reason - ECM Request | Engine Running | ECM tasks are currently running that will not allow an autostop | No | Autostop will function once the task is complete. | Inform Customer - Normal Disable Condition |
| Autostop Disable Reason - Run/Crank Not Active | Engine Running | Vehicle must be in Run Mode | No | Verify ECM Run/Crank signal | If OK: Inform Customer - Normal Disable Condition If not OK: refer to Power Mode Mismatch. |
| Autostop Disable Reason - Minimum Engine Run Time Not Met | Engine Running | Engine must run a minimum time before stop/start is allowed. | No | Autostop will function once the minimum run time is met | Inform Customer - Normal Disable Condition |
| Autostop Disable Reason - Control Function Active | Engine Running | Scantool control function active | No | Release control function in scantool | |
| Autostop Disable Reason - Auxiliary Transmission Fluid Pump/Accumulator Not Available | Engine Running | Transmission aux pump or accumulator not available | No | Check for transmission DTCs, refer to automatic transmission service information | As Required |
| Autostop Disable Reason - Engine Coolant Temperature Out of Range | Engine Running | Coolant temperature too hot or cold | No | Verify cooling temperature is within normal operating values | If OK: Inform Customer - Normal Disable Condition If not OK: Refer to Engine Heating and Cooling diagnostics. |
| Autostop Disable Reason - Invalid Data Received | Engine Running | ECM has received invalid data | No | Check ECM DTCs. | As Required |
| Autostop Disable Reason - Vehicle Speed Too High | Engine Running | Vehicle speed detected | No | Ensure vehicle is at a complete stop | If OK: Inform Customer - Normal Disable Condition If not OK: refer to SI |
| Autostop Disable Reason - Transmission Fluid Temperature Out of Range | Engine Running | Transmission temperature too hot or cold | No | Verify transmission temperature is within normal operating values | If OK: Inform Customer - Normal Disable Condition. If not OK: Refer to transmission diagnostics. |
| Autostop Disable Reason - Brake Pedal Released | Engine Running | Brake pedal not pressed (enough) | No | Ensure brake pedal is pressed sufficiently to active autostop | If OK: Inform Customer - Normal Disable Condition If not OK: Verify brake pedal switch operation and calibration. |
| Autostop Disable Reason - Brake Booster Weak Vacuum | Engine Running | Weak brake booster vacuum | No | Ensure brake booster vacuum is within normal operating values | Check DTCs. Refer to brake booster diagnostics. |
| Autostop Disable Reason - Accelerator Pedal Pressed | Engine Running | Accelerator pedal pressed | No | Ensure accelerator pedal is fully released | If OK: Inform Customer - Normal Disable Condition If not OK: Ensure pedal sensor operation and calibration. |
| Autostop Disable Reason - A/C Request | Engine Running | HVAC system is requesting AC compressor due to high cabin temperature and/or humidity | No | Allow cabin temperature/humidity to reach setpoint, change setpoint, turn off blower | Inform Customer - Normal Disable Condition |
| Autostop Disable Reason - Low-Voltage Battery Voltage Low | Engine Running | 12V battery voltage is low | No | Charge and test battery, operate vehicle for longer drives, check generator operation | |
| Autostop Disable Reason - Low-Voltage Battery State of Health Low | Engine Running | 12V battery has low state of health | No | Charge and test battery, operate vehicle for longer drives, check generator operation | |
| Autostop Disable Reason - Low-Voltage Battery State of Charge Low | Engine Running | 12V battery state of charge is low | No | Charge and test battery, operate vehicle for longer drives, check generator operation | |
| Autostop Disable Reason - Low-Voltage Battery Discharge Current High | Engine Running | Excessive current draw is placing a high demand on the generator | No | Check electrical loads, turn off unnecessary loads | Inform Customer - Normal Disable Condition |
| Autostop Disable Reason - Intake Manifold Weak Vacuum | Engine Running | Low manifold vacuum | No | Verify manifold vacuum | Check DTCs, refer to SI |
| Autostop Disable Reason - Engine Speed High | Engine Running | High idle condition | No | Correct cause of high idle | Check DTCs, refer to SI |
| Autostop Disable Reason - Wheel Slip Detected | Engine Running | Slippery road conditions | No | Ensure good road conditions | Inform Customer - Normal Disable Condition |
| Autostop Disable Reason - Vehicle Speed Threshold Not Reached | Engine Running | Vehicle must reach a minimum speed | No | Operate at sufficient speeds | Inform Customer - Normal Disable Condition |
| Autostop Disable Reason - Maximum Vehicle Stop Time Exceeded | Engine Running | Engine was shut off for maximum allowable off time | No | Operate at sufficient speeds to reactivate | Inform Customer - Normal Disable Condition |
| Autostop Disable Reason - Starter System Malfunction | Engine Running | No | Check ECM DTCs, refer to SI | As Required | |
| Autostop Disable Reason - System Malfunction | Engine Running | No | Check for Vehicle DTCs | As Required | |
| Autostop Disable Reason - Stop/Start Select Switch | Engine Running | Switch not enabled | No | Turn switch on. | If OK: Inform Customer - Normal Disable Condition If Not OK: refer to Stop/Start System Malfunction |
| Autostop Disable Reason - Idle Boost Mode Active | Engine Running | Idle boost requested | No | Check electrical loads, turn off unnecessary loads | Inform Customer - Normal Disable Condition |
| Autostop Disable Reason - Generator Load High | Engine Running | Excessive current draw is placing a high demand on the generator | No | Check electrical loads, turn off unnecessary loads | Inform Customer - Normal Disable Condition |
| Autostop Disable Reason - Clutch Pedal Applied | Engine Running | Clutch pedal (manual trans) not released | No | Ensure clutch pedal is released | If OK: Inform Customer - Normal Disable Condition If not OK: Refer to clutch switch diagnostic and verify calibration. |
| Autostop Disable Reason - Low-Voltage Battery Temperature Out of Range | Engine Running | Battery temperature too cold or hot | No | Ensure battery is kept within normal operating range | Inform Customer - Normal Disable Condition |
| Autostop Disable Reason - Low-Voltage Battery State of Function Low | Engine Running | 12V battery state of function low | No | Charge and test battery, operate vehicle for longer drives, check generator operation | |
| Battery Sensor Module Battery State Data | Engine Running | Battery Sensor Module | Available | Check ECM s/w version* | Perform Battery Sensor Module Learn |
The following Autostart Inhibit parameters show why the engine is off or was turned off. There are a couple different things this can mean. Forced Off (Mostly Hybrid), Propulsion System Shutdown (Stall), Cannot Start Engine (Hybrid).
Autostart Inhibit
| Scantool Parameter - Current Inhibit Reason | System State | Description | Expected Value | Recommended Check | Next Step |
|---|---|---|---|---|---|
| Autostart Inhibit Reason - Hood Ajar | Engine off | Hood not latched | No | Ensure hood is closed and latched. | If not OK: close hood. |
| Autostart Inhibit Reason - ECM Request | Engine off | ECM tasks are currently running that will not allow an autostart | No | Autostop will function once the task is complete. | Inform Customer - Normal Disable Condition |
| Autostart Inhibit Reason - Run/Crank Not Active | Engine off | Vehicle must be in Run Mode | No | Verify ECM Run/Crank signal | If OK: Inform Customer - Normal Disable Condition |
| Autostart Inhibit Reason - System Malfunction | Engine off | No | Check for Vehicle DTCs | As Required | |
| Autostart Inhibit Reason - Autostart Not Commanded | Engine off | Vehicle is in a normal autostop mode | Yes | Inform Customer - Normal Disable Condition | |
| Autostart Inhibit Reason - Crank Aborted | Engine off | ECM has disabled propulsion system | Check ECM DTCs | ||
| Autostart Inhibit Reason - Control Function Active | Engine off | Scantool control function active | No | Release control function in scantool | |
| Autostart Inhibit Reason - ECM System Malfunction | Engine off | ECM has disabled propulsion system | Check ECM DTCs | ||
| Autostart Inhibit Reason - Autostart/Autostop Malfunction | Engine off | ECM has disabled propulsion system | Check ECM DTCs | ||
| Autostart Inhibit Reason - Driver Exited Vehicle | Engine off | Seat belt unbuckled and driver's door opened. | No | Not in all vehicles. Verify seat belt and driver's door switches. | If OK: Inform Customer - Normal Disable Condition |
| Autostart Inhibit Reason - Engine Coolant Temperature Out of Range | Engine off | Coolant temperature too hot or cold | No | Verify cooling temperature is within normal operating values | If OK: Inform Customer - Normal Disable Condition |
The following Autostart Reasons parameters are only valid when Engine is Running. It indicates why we started the engine the last time it was autostarted.
Autostart Reasons
| Scantool Parameter - Current Inhibit Reason | System State | Description | Expected Value | Recommended Check | Next Step |
|---|---|---|---|---|---|
| Autostart Reason - TCM Demand | Engine Running | TCM has requested an autostart | No | Ensure transmission is in drive. Stop/start will not function in manual mode. | If OK: Inform Customer - Normal Disable Condition. If not OK: Refer to transmission diagnostics. |
| Autostart Reason - Reduced Engine Power Active | Engine Running | No | Check ECM DTCs. | As required. | |
| Autostart Reason - Maximum Autostop Time Exceeded | Engine Running | Maximum autostop time is limited. | No | Maximum autostop time is typically 2 minutes. | If OK: Inform Customer - Normal Disable Condition |
| Autostart Reason - Transmission Fluid Temperature Out of Range | Engine Running | Transmission temperature too hot or cold | No | Verify transmission temperature is within normal operating values | If OK: Inform Customer - Normal Disable Condition. If not OK: Refer to transmission diagnostics. |
| Autostart Reason - System Malfunction | Engine Running | No | Check for Vehicle DTCs | As required. | |
| Autostart Reason - Transmission in Reverse | Engine Running | Transmission was placed in reverse. | No | Ensure transmission is in drive. | If OK: Inform Customer - Normal Disable Condition. If not OK: Refer to transmission diagnostics. |
| Autostart Reason - Invalid Data Received | Engine Running | ECM has received invalid data | No | Check ECM DTCs. | As required. |
| Autostart Reason - Vehicle Speed Too High | Engine Running | Vehicle speed detected | No | Ensure vehicle is at a complete stop | If OK: Inform Customer - Normal Disable Condition |
| Autostart Reason - System Optimization | Engine Running | ECM has determined that the engine needs to be started. | No | Check DTCs. | If OK: Inform Customer - Normal Disable Condition |
| Autostart Reason - System Voltage Low | Engine Running | 12V battery state of charge is low. | No | Charge and test battery, operate vehicle for longer drives, check generator operation | If OK: Inform Customer - Normal Disable Condition |
| Autostart Reason - Acceleration Request | Engine Running | Accelerator pedal pressed | No | Ensure accelerator pedal is fully released | If OK: Inform Customer - Normal Disable Condition |
| Autostart Reason - Minimum Engine Run Time Not Met | Engine Running | Engine must run a minimum time before stop/start is allowed. | No | Autostop will function once the minimum run time is met | Inform Customer - Normal Disable Condition |
| Autostart Reason - Control Function Active | Engine Running | Scantool control function active | No | Release control function in scantool | |
| Autostart Reason - Auxiliary Transmission Fluid Pump/Accumulator Not Available | Engine Running | Transmission aux pump or accumulator not available | No | Check for transmission DTCs, refer to automatic transmission service information | As Required |
| Autostart Reason - Engine Coolant Temperature Out of Range | Engine Running | Coolant temperature too hot or cold | No | Verify cooling temperature is within normal operating values | If OK: Inform Customer - Normal Disable Condition |
| Autostart Reason - Transmission Range | Engine Running | Transmission not in Drive | No | Ensure transmission is in drive. Stop/start will not function in manual mode. | If OK: Inform Customer - Normal Disable Condition |
| Autostart Reason - Hood Ajar | Engine Running | Hood not latched | No | Ensure hood is closed and latched. | If not OK: close hood. |
| Autostart Reason - ECM Request | Engine Running | ECM tasks are currently running that will not allow an autostop | No | Autostop will function once the task is complete. | Inform Customer - Normal Disable Condition |
| Autostart Reason - Low-Voltage Battery Discharge Current High | Engine Running | Excessive current draw is placing a high demand on the generator | No | Check electrical loads, turn off unnecessary loads | Inform Customer - Normal Disable Condition |
| Autostart Reason - Brake Pedal Released | Engine Running | Brake pedal not pressed (enough) | No | Ensure brake pedal is pressed sufficiently to active autostop | If OK: Inform Customer - Normal Disable Condition |
| Autostart Reason - Brake Booster Weak Vacuum | Engine Running | Weak brake booster vacuum | No | Ensure brake booster vacuum is within normal operating values | Check DTCs. Refer to brake booster diagnostics. |
| Autostart Reason - Accelerator Pedal Pressed | Engine Running | Accelerator pedal pressed | No | Ensure accelerator pedal is fully released | If OK: Inform Customer - Normal Disable Condition |
| Autostart Reason - A/C Request | Engine Running | HVAC system is requesting AC compressor due to high cabin temperature and/or humidity | No | Allow cabin temperature/humidity to reach setpoint, change setpoint, turn off blower | Inform Customer - Normal Disable Condition |
| Autostart Reason - Low-Voltage Battery Voltage Low | Engine Running | 12V battery voltage is low | No | Charge and test battery, operate vehicle for longer drives, check generator operation | |
| Autostart Reason - Driver Exited Vehicle | Engine Running | Seat belt unbuckled and driver's door opened. | No | Not in all vehicles. Verify seat belt and driver's door switches. | If OK: Inform Customer - Normal Disable Condition |
| Autostart Reason - Clutch Pedal Applied | Engine Running | Clutch pedal (manual trans) not released | No | Ensure clutch pedal is released | If OK: Inform Customer - Normal Disable Condition |