COBB1
If you get either the COBB1 or COBB2 code, add Ethanol Volts to your datalog list. You can also add it to your gauges screen to view it live. This value will be in the 0.5-4.5 V range during normal operation. COBB1 values are below 0.25 V, and COBB2 values are over 4.75 V.
Depending on the voltage shown on the Ethanol Volts parameter, it may be indicative of a different issue.
COBB1 Voltage and Troubleshooting
0.0V - Power or ground supply fault
With the module showing 0 volts, there is potentially a missed or loose connection. It’s recommended that you start with checking connections all the connections on the harness. The power connections that go to the EBCS, NexGen flex fuel control module itself, as well as the TGV plugs.
For the system to operate properly, everything must be plugged in and seated properly in order for it to function. The control module connector requires firm pressure until there’s a click to lock it in place, due to the weather seal. If the COBB fuel pressure kit is also fitted, make sure the TGV connectors are arranged in the proper sequence. This is TGV Housing → NexGen Flex Fuel Kit → Fuel Pressure Kit → Engine Harness. Keep in mind that the DTC will remain until the ECU is reset via the Accessport, so after you think you’ve resolved the issue or unplugged and replugged the harness, it’s a good idea to clear codes and see if it comes up again. If the issue persists after reset, check fuses. If everything checks out then contact customer support for further assistance with power supply voltage and ground continuity checks if necessary.
0.1V - Potential connection fault between ethanol sensor and module, or potential ethanol sensor fault.
Check connections at EBCS and ethanol sensor. Confirm the connectors are secure, then see if Ethanol Volts is in the normal range (0.5-4.5V) on the Accessport. The DTC will remain until the ECU is reset via the Accessport. If the issue persists, contact customer support.
0.15V - Intermittent sensor connection fault
This is usually caused by severe jostling of the vehicle/ethanol sensor and we’ve incorporated multiple systems to prevent this from negatively impacting engine operation as much as possible, but if the NexGen flex fuel module receives persistent sensor data which is in error due to intermittent connection with the ethanol sensor, this can cause the COBB1 DTC, with error voltage 0.15
0.2V - Sensor Error, Internal Fault
Ethanol Sensor may have failed and need to be replaced.
C0BB2
This code comes up if the input voltage is over the DC limit for more than a few samples at a time. If you get either the COBB1 or COBB2 code, add Ethanol Volts to your datalog list. You can also add it to your gauges screen to view it live. This value will be over 4.75v if you are receiving a COBB2.
Depending on the voltage shown on the Ethanol Volts parameter, it may be indicative of a different issue.
COBB2 4.8V - Sensor/Fuel error, compensation out of range
This error is caused by the sensor or contaminated fuel. Remove fuel from the car if possible, flush fuel system with known good fuel, reset ECU, and see if issues returns. If persists, replace the ethanol content sensorsensor.
COBB2 4.9V - Fuel Error (Water Debris)
Remove fuel from the car if possible, flush fuel system with known good fuel. While water in your fuel is the most common cause of this voltage, debris or some fuel additives may prevent ethanol sensors from getting a proper reading if in high enough concentration. Remember to reset ECU after swapping the fuel out, to see if the issue persists.
COBB2 5.0V - Wiring Short
Check wiring for visible damage.