Page 27 Enhanced parameters are additional data that can be scanned from most late-model GM vehicles. The LS1 and L67/L36 support all of these listed below. Enhanced GM Parameters: (may not apply to all vehicles) Parameter Description Typical Value BARO Barometric pressure Depends on weather. Typically
29-30 inches of mercury. NOTE:
Doesn’t work on all cars
FTC Fuel trim cell Varies with engine conditions. In
general, numbers go up with
load, except for cells 20-22,
which may be used for open loop
(including full throttle)
IAC Idle air counts 20-60 at warm idle to 100 while
cruising; higher when a/c is on
IDC1
IDC2
Injector duty cycle, driver’s
side & passenger side
1-2% at idle, up to 85% at full
throttle
IGNV Ignition volts 12 volts or so with key on, down
to 9.5-9.8 during starting, then
13.5-14.5 with engine running
IPW1
IPW2
Injector pulse width 2-4 milliseconds up to 15-20 at
higher rpm’s and full throttle
KR Knock retard Zero to 3-4 degrees
Ideally, should always be zero
MAFF Mass air flow frequency 2200-2300 at idle, 9000+ at full
throttle
MISP Primary misfiring cylinder 1-8 if misfires present
MISR Revolutions with misfires 0-10 revs is common; more than
that may indicate problem
TFT Transmission Fluid
Temperature
Ambient to 200 deg F or so.
Above 225 and the tranny fluid
starts to deteriorate.
TPSV Throttle position sensor
voltage
0-5Volts; typically 0.5 volts at
idle & 4.5 at full throttle