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DIAGNOSTIC DATA, ECM
P/N 1227727

Template $8D
Used for "F", (Camaro) and "Y" Car,
(Vette)




Year Disp RPM VIN
90,
91
5.0 PFI LB9 F
90,
91
5.7 PFI L98 8



READ DATA ON PIN "M" OF ALDL
CONNECTOR

8192
BAUD - BI-DIRECTIONAL




MODE 0
The test
device must transmit the following message to the ECM after idle
line.
.
MESSAGE
ID
=
$F4
MESSAGE
LENGTH
=
$56
MODE =
$00
SUM
CHECK
=$57
ECM RESPONSE
The ECM will transmit the following
message.
MESSAGE
ID
=
$F4
MESSAGE
LENGTH
=
$56
MODE =
$00
Check
sum
=$57

MODE 1
Mode 1 will
only be active if requested by the test device.
MESSAGE
ID
=
$F4
MESSAGE
LENGTH
=
$56
MODE =
$01
MESSAGE
NUMBER
=
$00
Check
sum
=
$58
THE ECM WILL RESPOND WITH THE FOLLOWING
MESSAGE
:
MESSAGE
ID
=
$F4
MESSAGE
LENGTH
=
$95
MODE =
$01
DATA BYTE
1
.
DATA BYTE
63
Check
sum
=
$nn

MODE 10
Clear error codes
MESSAGE
ID
=
$F4
MESSAGE
LENGTH
=
$56
MODE =
$0A
CHECKSUM =$5C






63 DIAGNOSTIC DATA
WORDS




Function
1 EPROM ID,
(MSB)
2 EPROM ID,
(LSB)
3 MALFFLG1
MALFUNCTION WORD 1
b0 CODE 23, MAT
SENSOR LOW
b1 CODE 22, TPS
LOW
b2 CODE 21, TPS
HIGH
b3 CODE 16, NOT
USED
b4 CODE
15,COOLANT SENSOR LOW TEMP
b5 CODE 14,
COOLANT SENSOR HIGH TEMP
b6 CODE 13, o2
SENSOR
b7 CODE 12, NO
DPR's
4 ERROR
FLAG 2
b0 CODE 35 not
used
b1 CODE 34 MAP
SENSOR LOW
b2 CODE 33 MAP
SENSOR HIGH
b3 CODE 32 EGR
DIAGNOSTIC
b4 CODE 31 not
used
b5 CODE 26 not
used
b6 CODE 25 MAT
SENSOR HIGH
b7 CODE 24
Vss
5 ERROR
FLAG 3
b0 CODE 51
EPROM ERROR
b1 CODE 46 VATS
FAILED
b2 CODE 45 o2
RICH
b3 CODE 44 o2
SENSOR LEAN
b4 CODE 43 ESC
FAILURE
b5 CODE 42 EST
MONITOR ERROR
b6 CODE 41
CYLINDER SELECT ERROR
b7 CODE 36 not
used
6 ERROR
FLAG 4
b0 CODE 63 NOT
USED
b1 CODE 62 OIL
TEMP HIGH
b2 CODE 61 not
used
b3 CODE 56 not
used
b4 CODE 55 not
used
b5 CODE 54 FUEL
PUMP VOLTAGE
b6 CODE 53 OVER
VOLTAGE
b7 CODE 52 OIL
TEMP LOW
7 ERROR
FLAG 5
b0 not
used
b1 not
used
b2 not
used
b3 not
used
b4 not
used
b5 CODE 66 not
used
b6 CODE 65 not
used
b7 CODE 64 not
used
8 COOLANT
TEMPERATURE, A/D COUNTS
Deg c = n
x.75 - 40
9 START UP
COOLANT TEMPERATURE
Deg c = n
x.75 - 40
0 TPS A/D
COUNTS
VDC = n x
(5/255)
11 ENGINE
SPEED (RPM)
RPM = n x
25
12 NEW DRP,
TIME BETWEEN REFERENCE PULSES (MSB)
13 NEW DRP+1
TIME BETWEEN REFERENCE PULSES (LSB)
usec =
([n13]*256 + [n14]) x 15.26
14 MPH/1
15 NVMW2,
NON-VOLATILE MODE WORD 2
b0 not
used
b1 not
used
b2 not
used
b3 1 =
PLUGGABLE MEMORY FAILURE (err51)
b4 not
used
b5 1 = VATS
OK
b6 not
used
b7 1 = ESC
ENABLED BY DELTA COOLANT
16 ENG/Vss
RATIO TO DETERMINE GEAR
N =
RPM/MPH
17 OXYGEN
SENSOR
VOLTAGE = N
x 4.42
18 o2 SENSOR
RICH/LEAN TRANSITION COUNTER
19 BASE
PULSE (FUEL) C/L FINE CORRECTION
20 BLM
21 BLM CELL
Number
22 CLOSED
LOOP INTEGRATOR
23 IDLE
SPEED, PRESENT IAC MOTOR POSITION
Steps
24 SCALED
TPS, auto zero
%TPS =
N/2.56
25 DESIRED
IDLE SPEED, RPM/12.5
26 MANIFOLD
AIR PRESSURE, A/D CTS
VOLTS = N x
(5/255)
27 SC1 SDI
STATUS OF SC1 INPUT DISCRETES
b0 NOT
USED
b1 A/C LOW
PRESSURE SWITCH
b2 SECOND
GEAR
b3 NOT
USED
b4 NOT
USED
b5 A/C REQUEST
(0 = A/C REQUESTED)
b6 NOT
USED
b7 2ND FAN
REQUEST
28 FMD SDI
INPUT STATES TO FMD VIA SSR
b0 COOLANT
SWITCH (1 = 348 ohm, 0 = 4 K)
b1 COP2 ( <
54 usec BETWEEN FALLING EDGES)
b2 EST
ENABLE
b3 PORT,
PIN8
b4 FUEL PUMP
ENABLE
b5 not
used
b6 IRQ
ENABLE
b7 DATA STEER
(0 = BYTE 1, 1 = BYTE 2)
29 1 l NVMW1
NON-VOLATILE MODE WORD
30 MAT, A/D
COUNTS,
(See table)
31 EGR DUTY
CYCLE
%DC =
N/2.56
32 CHARCOAL
CANISTER PURGE DUTY CYCLE
%DC =
N/2.56
33 DIAGMW2
DIAGNOSTIC MODE WORD 2 (CURRENT MALF FLAGS)
b0 1 = err 41
INDICATED (CYLINDER SELECT ERR)
b1 1 = err 25
THIS PASS INDICATED
b2 1 = REF
PULSE IN CURRENT 100 msec.
b3 1 = DRP IN
LAST 100 msec.
b4 1 = err 54
LOCKED IN
b5 E = err 54
PRESENT
b6 b6 1 =
PASSED err 54A
b7 1 = ESC
ENABLED
34 BATTERY
VOLTAGE, A/D COUNTS
Vbatt =
n/10
35 FUEL PUMP
POWER
Vbatt =
n/10
36 DIAGMW4
DIAGNOSTIC MODE WORD 4 (CURRENT MALF FLAGS)
b0 1 = MALF 32
ACTIVE
b1 not
used
b2 1 = EGR
DIAGNOSTIC TEST IN WORK
b3 OPTION FOR 1
PASS
b4 TEST CYCLE
TIME FLAG
b5 1 = A/C
FIRST PASS WITH HIGH MPH
b6 1 = A/C
CLUTCH DISABLED DUE TO HIGH MPH
b7 1 = err 52
or 62 PRESENT
37 MIN
LEARNED IAC POSITION (KEEP ALIVE)
STEPS
38 LINEARIZED OIL TEMP (MSB) Deg c = n
x.75 - 40
39 TOTAL
UNLIMITED SPARK ADV. REL TO TDC (MSB)
40 TOTAL
UNLIMITED SPARK ADV. REL TO TDC (LSB)


Double byte value in 2's
complement representation

If Bit 7 of MSB = 0 then result
is positiv

Value = ([n41] x 256 + [n42])
If Bit 7 of MSB = 1 then result is
negative


Value = 65536 - ([n41] x 256 + [n42])

Deg Spk = value x
90/256
41 UNLIMITED
SPARK ADV. REL TO REF. PULSE (MSB)
42 TOTAL
UNLIMITED SPARK ADV. REL TO TDC (LSB)

Double byte value in 2's
complement representation

If Bit 7 of MSB = 0 then result is
positive


Value = ([n41] x 256 + [n42])

If Bit 7 of MSB = 1 then result is
negative


Value = 65536 - ([n41] x 256 + [n42])

Deg Spk = value x
90/256
43 ESC
(KNOCK) SIGNAL INPUT
COUNTS
44 ESC
(KNOCK RETARD)
Deg = n x
45/256
45 INJECTOR
BASE PULSE WIDTH (MSB)
46 OBPINJ +
1 INJECTOR BASE PULSE WIDTH (LSB)
msec =
([n45] x 256 + [n46])/65.536
47 TOTAL
FUEL AIR VALUE (FINAL) (MSB)
48 TOTAL
FUEL AIR VALUE (FINAL) (LSB)
A/F RATIO =
6553.6/([n47] x 256) + 6553.6/[n48]
49 RUNNING
TOTAL OF FUEL DELIVERED (MSB)
50 RUNNING
TOTAL OF FUEL DELIVERED (LSB)
usec =
([n49] x 256 + [n50])*15.26
51 RUNNING
TOTAL OF DISTANCE TRAVELED
Miles =
n/2000
52 ENGINE
RUNNING TIME IN SECONDS (MSB)
53 ENGINE
RUNNING TIME IN SECONDS (LSB)
Sec's =
([n52] x 256 + [n53])
54 Mode Word
2
b0 not
used
b1 MALF 14 OR
15 THIS START UP
b2 DRP, (6.25
MSEC CHECK)
b3 1 = IN CCM
MODE
b4 DIAGNOSTIC
SWITCH IN DIAG. POSITION
b5 DIAGNOSTIC
SWITCH IN ALDL POSITION
b6 HIGH BATTERY
VOLTAGE-DISABLE MCU SOL.DIS.
b7 SHIFT LIGHT,
1 = ON
55 Torque
Converter Clutch Mode Word
b0 1 = TCC
LOCKED
b1 1 = COAST
RELEASE

TPS THRESHOLD IN USE (HI
MPH)
b2 1 = 4-3/4-2
DOWNSHIFT RELEASE IN PROGRESS
b3 1 = STATUS
OF FOURTH GEAR LAST PASS
b4 1 = TCC
LOCKED FOR PASS BY NOISE
b5 not
used
b6 not
used
b7 not
used
56 Fuel
Modeling Device Byte 1
GEMERIC ALDL
BYTE = 44
b0 PARK/NEUTRAL
SWITCH (1 = DRIVE)
b1 1 = IN 3RD
OR 4TH GEAR
b2 1 = IN 4TH
GEAR
b3 0 = POWER
STEERING CRAMP - CHANGE FROM '89
b4 not
used
b5 not
used
b6 0 = HIGH A/C
HEAD PRESSURE INDICATED

(IF N.O.
SWITCH)
b7 1 = A/C
CLUTCH ENGAGED
57 Mode Word
1
b0 ADVANCE
FLAG, 0 = ADV., 1 = RTD
b1 1 = HIGHWAY
FUEL TIMER ENABLED
b2 INTERRUPT
SERVICE EXC. 6.25 msec
b3 1 = ALL FAN
1 PID STEPS ADDED

(FAN 1
ENABLED)
b4 1 = 1st PASS
WITH 1 ROAD SPEED PULSE
b5 AIR COND.
CLUTCH FLAG (0 = A/C CLUTCH ON)
b6 BYPASS CHECK
ENABLE
b7 ENGINE
RUNNING FLAG (1 = RUNNING)
58 Non
Volatile MW
b0 1 = 02
SENSOR READY
b1 1 = CLOSED
LOOP TIMER TIMED OUT
b2 not
used
b3 1 = BAD
SHUTDOWN
b4 Not
used
b5 1 = IAC
KICKDOWN ENABLED
b6 1 = KICKDOWN
ENABLED
b7 1 = err 42
FAILED (EST monitor)
59 Computer
Aided Ratio Selection Mode Word
b0 1 = CARS
DISABLED DUE TO LOW BAROMETRIC PRESSURE
b1 1 = CARS
ACTIVE
b2 not
used
b3 not
used
b4 1 =
TRANSMISSION IN 4th. GEAR
b5 1 =
TRANSMISSION IN 1st, GEAR
b6 1 = WAIT FOR
Vss RESET
b7 not
used
60 Closed
Loop CC Mode Word
b0 BOOKKEEPING
FLIP FLOP
b1 1 = Use F69
ALT TABLE
b2 1 =
IDLE
b3 1 =
UNDERSPEED IDLE SPARK, 0 = OVERSPEED
b4 1 = Decel
Fuel Cut Ooff STALL SAVER ENABLED
b5 1 = USING
KF93 MULT TRIM TO D-MAP A.E. ENABLE THRESHOLD
b6 1 = Non
Volatile. MEMORY BOMBED
b7 1 = Has been
in Closed Loop at least once since restart
61 AIR
MW
GENRERIC
ALDL BYTE = 18
b0 1 = 100 msec
OLD CCP PURGE ON FLAG (0 = OFF)
b1 1 = AIR
CONTROLLED, 0 = AIR DIVERTED
b2 1 = AIR
SWITCHED TO PORT (If air is controlled)
b3 1 = FAN 1
REQUESTED
b4 1 = FAN 2
REQUESTED
b5 1 = 'OLD'
FAN 1 STATE WAS ON
b6 1 = ALL FAN
2 PID STEPS ADDED (Fan 2 enabled)
b7 1 = DECEL
ENLEANMENT ACTIVE
62 LCCP
MW
b0 1 = CAN
PURGE ACTIVE
b1 1 = TIME
1st. REF TO ENG RUN
b2 1 = MALFS
HAVE OCCURRED
b3 1 = IN 8192,
Mode 4, Bypass fuel mode
b4 2nd. TIME COOLANT
b5 1 = err 43A
(voltage presence check) Indicated
b6 1 = KICKDOWN
REQUEST
b7 1 = TIME OUT
FINISHED
63 Mode Word
Fuel/Air 1
b0 1 = IN
SINGLE FIRE MODE
b1 BLM ENABLE
FLAG, 1 = ENABLE STORE
b2 1 = DELIVER
0 FUEL (Single fire)
b3 1 = ALLOW
SINGLE FIRE DISABLE
b4 1 = VEHICLE
SPEED SENSOR FAILURE
b5 1 = EECC
SLOW 02 RICH, 0 = SLOW 02 LEAN
b6 RICH-LEAN
FLAG (1 = RICH, 0 = LEAN)
b7 CLOSED LOOP
FLAG, 1 = CLOSE
D LOOP