$8d ECU Diagnostic Data Stream Returned in Mode 1 by ECM guy

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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 = CLOSED LOOP