PCM Diagnostics & Tuning HP Tuners | Holley | Diablo

ECU trouble

Old Apr 11, 2006 | 09:23 PM
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Default ECU trouble??

I've been having trouble getting my Autometer tach to work. I've sent it back to Autometer a few times and it sill doesn't work. Its calibrated for the 5 volt signal, so that's not the problem.
One problem I do have is when checking the voltage out of the ECU it reads .14 volts DC. Is it possible that my ECU is bad? The car runs fine now.
My ABS light is lit. I thought that it was from putting in a 9" rear in but could it be from a low voltage reading from that pin? (Pin 10)

Last edited by Ryan'sSS; Apr 12, 2006 at 07:55 AM.
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Old Apr 12, 2006 | 07:55 AM
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Need some help please.
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Old Apr 12, 2006 | 08:59 AM
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There are some tachs which load down the tach signal
too much to work as-is, the drive is weak on this
"convenience" output. You may need to add a pullup
resistor to get the necessary swing (this is not a DC
signal and measuring it with a DMM will tell you little).
Try clipping something like a 1K resistor from the tach
wire to one of the PCM +5V outputs and see it things
start working for you. Supposedly the average voltage
should be 2.5V as you'd expect off a square wave 5V
signal. Some pullup assist might make that happen if
it's just a line loading deal.
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Old Apr 12, 2006 | 09:55 AM
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Ok, stupid question here. Where can I find a +5 volt signal, i.e. which wire?
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Old Apr 12, 2006 | 03:48 PM
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ttt...
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Old Apr 13, 2006 | 07:37 AM
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bump..
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Old Apr 13, 2006 | 09:05 AM
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'99-'02 PCM connector pinout info:

Connector Part Information
PCM Connector C1 12191489
80 Way Micro-Pack 100W Series Sealed (BLU)

Pin
Wire Color
Circuit No.
Function

1
BLK
451
PCM Ground

2
LT GRN
1867
12 Volt Reference

3
PNK/BLK
1746
Fuel Injector 3 Control

4
LT GRN/BLK
1745
Fuel Injector 2 Control

5-7
--
--
Not Used

8
GRY
596
5 Volt Reference


9-10
--
--
Not Used

11
LT BLU
1876
KS 2 Signal

12
DK BLU/WHT
1869
CKP Sensor Signal

13-16
--
--
Not Used

17
DK BLU
1225
Transmission Fluid Pressure Switch Signal B

18
RED
1226
Transmission Fluid Pressure Switch Signal C

19
PNK
439
Ignition 1 Voltage

20
ORN
340
Battery Positive Voltage

21
YEL/BLK
1868
Low Reference

22
--
--
Not Used

23
GRY
720
Low Reference

24
--
--
Not Used

25
TAN
1671
HO2S Low Signal Bank 2 Sensor 2

26
TAN
1667
HO2S Low Signal Bank 2 Sensor 1

27
--
--
Not Used

28
TAN/WHT
1669
HO2S Low Signal Bank 1 Sensor 2

29
TAN/WHT
1653
HO2S Low Signal Bank 1 Sensor 1

30-31
--
--
Not Used

32
GRY
48
CPP Switch Signal

33
PPL
420
TCC Brake Switch Signal

34
ORN/BLK
434
Neutral Safety Switch Signal

35
--
--
Not Used

36
BLK
1744
Fuel Injector 1 Control

37
YEL/BLK
846
Fuel Injector 6 Control

38-39
--
--
Not Used

40
BLK
451
Ground

41
--
--
Not Used

42
DK GRN
335
Low Speed Cooling Fan Relay Control

43
RED/BLK
877
Fuel Injector 7 Control

44
LT BLU/BLK
844
Fuel Injector 4 Control

45
GRY
474
5-volt Reference A/C Refrigerant Pressure Sensor

46
GRY
474
5-volt Reference Fuel Tank Pressure Sensor

47
--
--
Not Used

48
GRY
416
5-volt Reference MAP Sensor

49-50
--
--
Not Used

51
DK BLU
496
KS 1 Signal

52
--
--
Not Used

53
BLK
407
Low Referecne Transmission Temperature Sensor

54
BLK
407
Low Reference MAP Sensor

55
--
--
Not Used

56
--
--
Not Used

57
ORN
340
Battery Positive Voltage

58
DK GRN
1049
ECM/PCM/VCM Class 2 Serial Data

59
--
--
Not Used

60
BLK
452
Low Reference

61
PNK/BLK
632
Low Reference Camshaft Position Sensor

62-64
--
--
Not Used

65
PPL
1670
HO2S High Signal Bank 2 Sensor 2

66
PPL
1666
HO2S High Signal Bank 2 Sensor 1

67
--
--
Not Used

68
PPL/WHT
1668
HO2S High Signal [Bank 1 Sensor 2

69
PPL/WHT
1665
HO2S High Signal Bank 1 Sensor 1

70
BRN
1174
Oil Level Switch Signal

71-72
--
--
Not Used

73
BRN/WHT
633
CMP Sensor Signal

74
YEL
410
ECT Sensor Signal

75
--
--
Not Used

76
BLK/WHT
845
Fuel Injector 5 Control

77
DK BLU/WHT
878
Fuel Injector 8 Control

78
--
--
Not Used

79
GRY or WHT
587 or 687
Skip Shift Solenoid Control M/T or 3-2 Shift Solenoid Control A/T

80
BLK
407
Low Reference










Connector Part Information
PCM Connector C2 12191488
80 Way Micro-Pack 100W Series Sealed (RED)


Pin
Wire Color
Circuit No.
Function

1
BLK
451
Ground

2
BRN
418
TCC Solenoid - Output - PWM

3
--
--
Not Used

4
PNK/BLK
429
Air Injection Reaction Solenoid Relay - Coil - Control

5
--
--
Not Used

6
RED/BLK
1228
PC Solenoid Valve High Control Sol.A

7
--
--
Not Used

8
LT BLU/WHT
1229
PC Solenoid Valve Low Control Sol.A

9
DK GRN/WHT
465
Fuel Pump Relay Control Primary

10
WHT
121
Engine Speed Signal

11-12
--
--
Not Used

13
WHT
85
Cruise Control Engage Signal

14
RED/BLK
380
A/C Refrigerant Pressure Sensor Signal

15
RED
225
Generator Turn ON Signal

16
--
--
Not Used

17
DK GRN/WHT
762
A/C Request Signal

18
DK GRN
59
A/C Compressor Clutch Supply Voltage

19
--
--
Not Used

20
LT GRN/BLK
822
VSS Low Signal

21
PPL/WHT
821
VSS High Signal

22-23
--
--
Not Used

24
DK BLU
417
TP Sensor Signal

25
TAN
472
IAT Sensor Signal

26
PPL
2121
IC 1 Control

27
RED
2127
IC 7 Control

28
LT BLU/WHT
2126
IC 6 Control

29
DK GRN/WHT
2124
IC 4 Control

30
DK BLU
229
Fuel Enable Control

31
YEL
492
MAF Sensor Signal

32
LT GRN
432
MAP Sensor Signal

33
DK BLU
473
High Speed Cooling Fan Relay Control

34
DK GRN/WHT
428
EVAP Canister Purge Solenoid Control

35
--
--
Not Used

36
BRN
436
AIR Pump Relay Control

37
DK GRN
83
Cruise Control Inhibit Signal

38
--
--
Not Used

39
RED
631
12 Volt Reference

40
BLK
451
Ground

41
--
--
Not Used

42
TAN/BLK
422
TCC Solenoid Valve Control

43
DK GRN/WHT
459
A/C Clutch Relay Control

44
LT GRN
1652
Reverse Lock Out Solenoid Control

45
WHT
1310
EVAP Canister Vent Solenoid Control

46
BRN/WHT
419
MIL Control

47
YEL/BLK
1223
2 - 3 Shift Solenoid Valve Control

48
LT GRN
1222
1 - 2 Shift Solenoid Valve Control

49
--
--
Not Used

50
DK GRN/WHT
817
VSS Signal

51
YEL/BLK
1227
TFT Sensor Signal

52
--
--
Not Used

53
GRY/BLK
1687
Ignition Retard Signal

54
PPL
1589
Fuel Level Sensor Signal

55-56
--
--
Not Used

57
PPL
719
Low Reference

58-59
--
--
Not Used

60
BRN
2129
Low Reference

61
BRN/WHT
2130
Low Reference

62
--
--
Not Used

63
PNK
1224
Transmission Fluid Pressure Switch Signal A

64
DK GRN
890
Fuel Tank Pressure Sensor Signal

65
--
--
Not Used

66
PPL/WHT
2128
IC 8 Control

67
RED/WHT
2122
IC 2 Control

68
DK GRN
2125
IC 5 Control

69
LT BLU
2123
IC 3 Control

70-75
--
--
Not Used

76
LT GRN/WHT
1749
IAC Coil B High Control

77
LT GRN/BLK
444
IAC Coil B Low Control

78
LT BLU/BLK
1748
IAC Coil A Low Control

79
LT BLU/WHT
1747
IAC Coil A High Control

80
--
--
Not Used


Courtesy of MattH
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Old Apr 13, 2006 | 09:14 AM
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Thank you very much.
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Old Apr 15, 2006 | 12:53 PM
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Just got done trying that and it didn't work. Is there any way the drive could be fried?
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Old Apr 15, 2006 | 06:08 PM
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Also, is there another place I can get a signal to drive a tach and a window switch?
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Old Apr 23, 2006 | 07:01 PM
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Did you get that fixed yet? I got mine working by using a 1 k resistor from the tach line to the 12v that powers the tach.

LM
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