I put a Z06 blower on a Z51 engine and the tuner is working thru the final little issues. One nagging error is Reduced Engine Output and when I still had the car the two error codes were on air flow and map measurement. Any suggestions as to what the problem may be? The air flow sensor is the one that came with the car originally. The tmap sensor is a GM part that is supposed to be a stock Z06 sensor. Which would be, what, 2-1/2 bar? All suggestions appreciated.

 

Z06 has 3 Inlet Temperature sensors. Two of them are located with the MAF and IAT3 is part of the manifold pressure sensor that is located at the rear of the driver's side intake manifold log. I don't know whether the LT1 uses the same configuration of sensors at the MAF so that may be something to check.

Summarized from my 2015 FSM:

The LT4 has three IAT Sensors:

IAT 1 and 2 are part of the Multifunction Intake Air Sensor which also includes the Humidity, MAF and Barometric sensors. IAT2 doesn't tell you what the charge air temp is. It is part of Module B75C. DTCs related to these two sensors are: P0096 IAT2 Performance; P0097 IAT2 Low Voltage; P0098 IAT2 High Voltage; P0099 IAT2 Voltage Intermittent; P0111 IAT1 Performance; P0112 IAT1 Low Voltage; P0113 IAT1 High Voltage; P00114 IAT1 Intermittent.

IAT3 is integrated with the Intake Manifold Pressure and Air Temperature Sensor which is located at the back of the S/C housing so it can measure charge air pressure and temperature. It is part of Module B65. DTCs related to this sensor are: P00E9 IAT3 Performance; P00EA IAT3 Low Voltage; P00EB IAT3 High Voltage; P00EC IAT3 Intermittent.

Bill

 

The two codes I’m getting are:
P1101: Induction Air Measurement, Cross-check out of range
P2227 Barometric pressure sensor ‘A’ circuit range/performance

If my tuner clears these issues, does tie Reduced Engine Output indication stay on for a few more cycles before it clears? My tuner says the car performs well otherwise

 

Looks to me like you need to check the wiring to and from the MAF Assembly. P1101 is called Intake Air Flow System Performance I guess it could be looked at as a Cross Check but it is just a check of the actual air flow based on Throttle Position Vs a calculated air flow based on the MAP and MAF sensor signals. P2227 shows a problem with the barometric sensor that is located in the MAF assembly. Those are all on the input to the engine and shouldn't be upset by having a SC sitting in place of the normal intake manifold. Since P1101 depends on having the correct MAP reading you could have a wiring issue with getting the MAP signal from Module B65 at the back side of the SC to the ECM.

The schematics show the same module is used for both the LT1 and LT4. IAT2 measured at the MAF is used by both the LT1 and LT4. IAT1 signal is seen at Pin 1 of the module and IAT2 is seen at Pin 8 of the module.

Although the same module is used it is wired into the system differently depending on the engine. The LT4 barometric sensor is wired to different pins on the ECM. Pin 2 of the Multifunction Intake Air Sensor (Module B75C) is wired to Connector X1 Pin 5 on the LT1 ECM and to Connector X2 Pin 64 on the LT4 ECM. Also, Pin 4 of the Multifunction Intake Air Sensor is wired to Connector X1 Pin 4 on the LT1 ECM and to Connector X2 Pin Pin 45 on the LT4 ECM. That indicates the LT4 harness that goes from the ECM to the MAF is different than the harness used for the LT1.

Bill

 

I broke out my factory manual with wiring diagram and compared it to my conversion kit’s jumpers. My kit removes the temperature compensation wire from the MAF and reroutes it to the pressurized manifold sensor for the supercharger. That explains the error code for the MAF and probably the P2227 code also. There also is no blower inlet temp/press sensor on the blower in my kit as in the LT4 for lack of wiring. I’ll just have to get my tuner to turn that temperature compensation function off at the MAF and that should eliminate the Reduced Engine Output error.

 

If I can help with this email me… I did this conversion first and know all the ins and outs..

bencharles_10@hotmail.com