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Thought it may be worth shedding some light on the issue mentioned where the MAP and Boost readings are reading lower than expected on some Toyota 1KD models like the Prado/Hilux when connected to generic scantools and OBD gauges like scangauge/torque pro/car scanner etc but are correct readings when you check on Techstream.
(Hope this is not too technical and makes sense).
Most ECMs reporting the MAP sensor reading via OBDII Mode 01 PID 0B, scaled as 0 - 255 kPa in a 8 bit message so 1 count = 1 kPa.
Problem is some (but not all) Toyota 1KDs ECMs have a MAP sensor range of 0 - 320 kPa which is 1 count = 1.2549 kPa. This max MAP reading correction is advised to the test equipment via the Mode 01 4F PID (which Techstream uses to make the correction).
If the scantool/OBD gauge does not have the ability to check for PID 4F and adjust the scaling automatically the MAP and Boost readings being displayed will be around 20kPa or 3 PSI lower than actual with ign on and engine not started and at idle (so around 78 kPa MAP or -3 PSI Boost and the error compounds as the turbo adds boost).
This issue has caused countless grief and unnecessary faultfinding on affected models using these tools, so worth knowing to save the angst.
On a scangauge you can check if the correction is needed using this x-gauge: (if you get No Data or Blank Response its not applicable. If the response is 320 the corrected MAP value is needed)
TXD: 07DF014F
RXF: 02E80441054F
RXD: 4008
MTH: 000A00010000
Name: MST (MAP Scaling Test)
If the correction is needed, here are the revised MAP and Boost x-gauges that hopefully fix
MAP:
TXD: 07DF010B
RXF: 02E80441050B
RXD: 2808
MTH: 0064007D0000 (x100 / 125 +0 which adds 1.25 scaling)
Name: MaP (in kPa)
TXD: 07DF010B
RXF: 02E88441050B
RXD: 2808
MTH: 005800320000 (x88 / 50 + 0 which adds 1.25 scaling and converts to PSI as XX.X)
Name: MaP (in PSI)
BOOST:
TXD: 07DF010B
RXF: 02E80441050B
RXD: 2808
MTH: 0064007DFF9B (x100 / 125 -101 which adds 1.25 scaling and subtracts 101 kPA sea level atmospheric pressure)
Name: BsT (in kPa)
TXD: 07DF010B
RXF: 02E88441050B
RXD: 2808
MTH: 00580032FF6D (x88 / 50 -147 which adds 1.25 scaling, converts to PSI and subtracts 14.7 PSI sea level atmospheric pressure)
Name: BsT (in PSI)
If your local barometric pressure is lower that 101 kPa /14.7 PSI then the last four digits in the MTH can be adjusted to correct for the difference, but the error is generally no more than 3 kPA or 0.5 PSI so not significant (but below are the different values to use).
101 = FF9B 14.7 = FF6D
100 = FF9C 14.6 = FF6E
99 = FF9D 14.5 = FF6F
98 = FF9E 14.4 = FF70
97 = FF9F 14.3 = FF71
96 = FFA0 14.2 = FF72
(Hope this is not too technical and makes sense).
Most ECMs reporting the MAP sensor reading via OBDII Mode 01 PID 0B, scaled as 0 - 255 kPa in a 8 bit message so 1 count = 1 kPa.
Problem is some (but not all) Toyota 1KDs ECMs have a MAP sensor range of 0 - 320 kPa which is 1 count = 1.2549 kPa. This max MAP reading correction is advised to the test equipment via the Mode 01 4F PID (which Techstream uses to make the correction).
If the scantool/OBD gauge does not have the ability to check for PID 4F and adjust the scaling automatically the MAP and Boost readings being displayed will be around 20kPa or 3 PSI lower than actual with ign on and engine not started and at idle (so around 78 kPa MAP or -3 PSI Boost and the error compounds as the turbo adds boost).
This issue has caused countless grief and unnecessary faultfinding on affected models using these tools, so worth knowing to save the angst.
On a scangauge you can check if the correction is needed using this x-gauge: (if you get No Data or Blank Response its not applicable. If the response is 320 the corrected MAP value is needed)
TXD: 07DF014F
RXF: 02E80441054F
RXD: 4008
MTH: 000A00010000
Name: MST (MAP Scaling Test)
If the correction is needed, here are the revised MAP and Boost x-gauges that hopefully fix
MAP:
TXD: 07DF010B
RXF: 02E80441050B
RXD: 2808
MTH: 0064007D0000 (x100 / 125 +0 which adds 1.25 scaling)
Name: MaP (in kPa)
TXD: 07DF010B
RXF: 02E88441050B
RXD: 2808
MTH: 005800320000 (x88 / 50 + 0 which adds 1.25 scaling and converts to PSI as XX.X)
Name: MaP (in PSI)
BOOST:
TXD: 07DF010B
RXF: 02E80441050B
RXD: 2808
MTH: 0064007DFF9B (x100 / 125 -101 which adds 1.25 scaling and subtracts 101 kPA sea level atmospheric pressure)
Name: BsT (in kPa)
TXD: 07DF010B
RXF: 02E88441050B
RXD: 2808
MTH: 00580032FF6D (x88 / 50 -147 which adds 1.25 scaling, converts to PSI and subtracts 14.7 PSI sea level atmospheric pressure)
Name: BsT (in PSI)
If your local barometric pressure is lower that 101 kPa /14.7 PSI then the last four digits in the MTH can be adjusted to correct for the difference, but the error is generally no more than 3 kPA or 0.5 PSI so not significant (but below are the different values to use).
101 = FF9B 14.7 = FF6D
100 = FF9C 14.6 = FF6E
99 = FF9D 14.5 = FF6F
98 = FF9E 14.4 = FF70
97 = FF9F 14.3 = FF71
96 = FFA0 14.2 = FF72