"Going Mafless" in COS Tutorial?

[DrX]

The tutorial Gives the following instructions:

Set the

Engine Diagnostics->Engine Diagnostics->MAF->Parameters: • {C2901} MAF High Frequency Fail 1: 1Hz • {C2902} MAF High Frequency Fail 2: 1Hz If calibration {C2902} is not available in the operating system that you are using, then ignore this step. • {C2903} MAF High Frequency Fail Limit: 1 • {C2907} MAF Test Min Engine Speed: 300 RPM • {C2908} MAF Test Min Run Time: 0.1 seconds

It appears to me that this will only result in a MAF fail if the MAF is still plugged in as the MAF frequency will never be equal to or greater than 1 if it is unplugged. Would it not be more appropriate to set C2904 to 20000 and C2906 to 1 if the MAF is permanently removed so that SD mode is triggered immediately?

[L31Sleeper]

If you unplug it all you have to worry about is the Check Engine Light trigger (C6001)
and the transmission full pressure triggers (E0102)

-Justin

[DrX]

I am trying to undersatand how this relates to this freeze frame data from a tune that is setup as per the above. I am told that the MAF is unplugged. Engine run time was 213 sec and the engine was in boost at 4079 RPM when the DTC set. P2101 was set at the same time -actual TP(64%) does not match desired TP(72%). Also, according to his C3906 TP should be under 56% at 4079 RPM.

Diagnostic Trouble Codes
P2101 "Control Module Throttle Actuator Position Performance" EPA ($10) "Powertrain Control Module (PCM)"
P2101 "Control Module Throttle Actuator Position Performance" EPA Pending ($10) "Powertrain Control Module (PCM)"
P0102 "Mass Air Flow (MAF) Sensor Circuit Low" PHC ($10) "Powertrain Control Module (PCM)"
P2101 "Control Module Throttle Actuator Position Performance" MPHC ($10) "Powertrain Control Module (PCM)"
C0035 "Left Front Wheel Speed Sensor Circuit" M ($29) "Electronic Brake Control Module (EBCM)"

History data
"Control Module Throttle Actuator Position Performance"
Subsystem Category Of DTC P
Fuel System Bank-1 OL
Fuel System Bank-2 OL
Calculated Load Value 0.8 %
Engine Coolant Temperature 88 °C 190 °F
Short Term Fuel Trim - Bank 1 0.0 %
Long Term Fuel Trim - Bank 1 0.0 %
Short Term Fuel Trim - Bank 2 0.0 %
Long Term Fuel Trim - Bank 2 0.0 %
Intake Manifold Absolute Pressure 168.0 kPa 24.4 PSI
Engine RPM 4079 RPM
Vehicle Speed Sensor 118 KMH 73 MPH
Air Flow Rate From Mass Air Flow Sensor 1.63 Grams/s 0.22 Lbs/Min
Absolute Throttle Position 63.5 %
TCC PWM Solenoid Command Off
Exhaust Gas Recirculation Valve Sensor Voltage 0.0 V
Fuel Temperature 95 °C 203 °F
Fuel Tank Pressure Sensor Voltage 1.4 V
Exhaust Gas Recirculation Valve Position 0.0 %
Engine Coolant Temperature At Startup 94 °C 201 °F
Desired Idle Speed 800 RPM
Desired Exhaust Gas Recirculation Valve Position 0.0 %
Barometric Pressure 104.4 kPa 15.1 PSI
Commanded Air Fuel Ratio B - LS2 12.0 :1
Engine Run Time 213 Seconds
Misfire Current Status 255 Counts
Mileage Since Last Code Cleared 0 Km 0 Miles
Odometer When Last Code Set Was Cleared 0 Km 0 Miles
Freeze Frame Counter 0 Counts
Freeze Frame Pass Counter 0 Counts
Freeze Frame Not Run Counter 0 Counts
Injector Base Pulse Width Bank 1 10.452 ms
Injector Base Pulse Width Bank 2 10.452 ms
ETC Average Pedal Position 48 Counts
ETC Indicated Throttle Position 64 %
Alcohol In Fuel Percentage 0.0 %
ETC Desired Throttle Position 72 %
Accelerator Pedal Position 68 %
Flex Fuel Sensor Frequency 0 Hz

"Control Module Throttle Actuator Position Performance"
Subsystem Category Of DTC P
Fuel System Bank-1 OL
Fuel System Bank-2 OL
Calculated Load Value 3.5 %
Engine Coolant Temperature 94 °C 201 °F
Short Term Fuel Trim - Bank 1 0.0 %
Long Term Fuel Trim - Bank 1 0.0 %
Short Term Fuel Trim - Bank 2 0.0 %
Long Term Fuel Trim - Bank 2 0.0 %
Intake Manifold Absolute Pressure 51.0 kPa 7.4 PSI
Engine RPM 1209 RPM
Vehicle Speed Sensor 0 KMH 0 MPH
Air Flow Rate From Mass Air Flow Sensor 1.63 Grams/s 0.22 Lbs/Min
Absolute Throttle Position 18.4 %
TCC PWM Solenoid Command Off
Exhaust Gas Recirculation Valve Sensor Voltage 0.0 V
Fuel Temperature 93 °C 199 °F
Fuel Tank Pressure Sensor Voltage 1.4 V
Exhaust Gas Recirculation Valve Position 0.0 %
Engine Coolant Temperature At Startup 94 °C 201 °F
Desired Idle Speed 800 RPM
Desired Exhaust Gas Recirculation Valve Position 0.0 %
Barometric Pressure 104.4 kPa 15.1 PSI
Commanded Air Fuel Ratio B - LS2 13.9 :1
Engine Run Time 1 Seconds
Misfire Current Status 0 Counts
Mileage Since Last Code Cleared 0 Km 0 Miles
Odometer When Last Code Set Was Cleared 0 Km 0 Miles
Freeze Frame Counter 0 Counts
Freeze Frame Pass Counter 0 Counts
Freeze Frame Not Run Counter 0 Counts
Injector Base Pulse Width Bank 1 1.404 ms
Injector Base Pulse Width Bank 2 1.404 ms
ETC Average Pedal Position 0 Counts
ETC Indicated Throttle Position 19 %
Alcohol In Fuel Percentage 0.0 %
ETC Desired Throttle Position 19 %
Accelerator Pedal Position 0 %
Flex Fuel Sensor Frequency 0 Hz

"Mass Air Flow (MAF) Sensor Circuit Low"
Subsystem Category Of DTC P
Fuel System Bank-1 OL
Fuel System Bank-2 OL
Calculated Load Value 0.8 %
Engine Coolant Temperature 88 °C 190 °F
Short Term Fuel Trim - Bank 1 0.0 %
Long Term Fuel Trim - Bank 1 0.0 %
Short Term Fuel Trim - Bank 2 0.0 %
Long Term Fuel Trim - Bank 2 0.0 %
Intake Manifold Absolute Pressure 168.0 kPa 24.4 PSI
Engine RPM 4079 RPM
Vehicle Speed Sensor 118 KMH 73 MPH
Air Flow Rate From Mass Air Flow Sensor 1.63 Grams/s 0.22 Lbs/Min
Absolute Throttle Position 63.5 %
TCC PWM Solenoid Command Off
Exhaust Gas Recirculation Valve Sensor Voltage 0.0 V
Fuel Temperature 95 °C 203 °F
Fuel Tank Pressure Sensor Voltage 1.4 V
Exhaust Gas Recirculation Valve Position 0.0 %
Engine Coolant Temperature At Startup 94 °C 201 °F
Desired Idle Speed 800 RPM
Desired Exhaust Gas Recirculation Valve Position 0.0 %
Barometric Pressure 104.4 kPa 15.1 PSI
Commanded Air Fuel Ratio B - LS2 12.0 :1
Engine Run Time 213 Seconds
Misfire Current Status 255 Counts
Mileage Since Last Code Cleared 0 Km 0 Miles
Odometer When Last Code Set Was Cleared 0 Km 0 Miles
Freeze Frame Counter 0 Counts
Freeze Frame Pass Counter 0 Counts
Freeze Frame Not Run Counter 0 Counts
Injector Base Pulse Width Bank 1 10.452 ms
Injector Base Pulse Width Bank 2 10.452 ms
ETC Average Pedal Position 48 Counts
ETC Indicated Throttle Position 64 %
Alcohol In Fuel Percentage 0.0 %
ETC Desired Throttle Position 72 %
Accelerator Pedal Position 68 %
Flex Fuel Sensor Frequency 0 Hz

[DrX]

Looking through the tune some more I also found that B6612 has all cells maxed to 100 and that B3208(Pedal Response Alternate) is set much lower than B3207(Pedal Response Primary) with max TP in B3208 being 62.5%.

Edit: Just informed that the vehicle is not equipped with Traction Control, but does have a Tow/haul switch.

[L31Sleeper]

I don't see these issues being MAF related..........I could be wrong ??

-Justin

[DrX]

There are other issues as I mentioned, but I'm wondering why the MAF fail was not triggered until 3.5 minutes of drive time had elapsed? Would the vehicle be in SD mode without a MAF fail being set?

[L31Sleeper]

There are other issues as I mentioned, but I'm wondering why the MAF fail was not triggered until 3.5 minutes of drive time had elapsed? Would the vehicle be in SD mode without a MAF fail being set?

Yes, you can unplug it and disable the Fault Enablers and it will never fail.
but it will run in SD mode because it has no data from the MAF.

[joecar]

A MAF DTC is required to be present for failover to SD.