... I'm also pulling together a list of the function abbreviations and their (very basic) definitions. If anyone can shed some light on these remaining few definitions I need, I'll wrap that up and post it as well ...
Jeff: Here's my 'ultimate listing of all ECM terminal labels for 1995.5 - 2004'. I've pulled it together from a brute-force search through all the FSM engine control wiring diagrams for both 4- and 6-cylinder Tacos. It only includes labels used for the terminals on the engine control module (ECM) itself.
1995.5 - 2004 Tacoma ECM Terminal Labels
This is a reference listing of Engine Control Module (ECM) terminal labels or names for 1995.5 through 2004 Toyota Tacomas - both 4-cylinder and 6-cylinder. Toyota FSM documentation often uses these labels in describing circuit connections or the 'logical layout' of the engine control wiring scheme.
This data was compiled from FSM engine control wiring diagrams.
These labels do not necessarily or consistently identify a particular physical pin or connector. To identify specific connectors and pins you need to refer to the factory wiring diagrams.
The terminal labels / names varied from 1995.5 through 2004. It is not the case that all labels apply to all ECM's, or that all ECM's have connections associated with all listed labels.
FORMAT for this listing:
The listing is in alphabetical order. Each entry has 3 possible parts or segments.
Name / Function (as listed in FSM) / Component to Which it Connects ECM
If the function associated with a given terminal is 'known' (explicitly listed in FSM) the terminal name and function are listed.
If function is not explicitly explained in the FSM wiring documentation, a '?' is listed, along with the name of the component to which the connection leads from the ECM (in parentheses).
If a label was used in more than one way, or if its apparent meaning is not consistent on all diagrams, it is broken out into multiple entries.
LIST OF ECM TERMINAL LABELS / NAMES:
#10 Injector control output (4-cyl and 5VZ)
#20 Injector control output (4-cyl and 5VZ)
#30 Injector control output (Some 4-cyl)
#30 Injector control output (5VZ)
#40 Injector control output (Some 4-cyl)
#40 Injector control output (5VZ)
#50 Injector control output (5VZ)
#60 Injector control output (5VZ)
4WD Detection switch input to signal whether vehicle is in 4WD
AC1 Input signal from air conditioning magnetic clutch
ACT ? (A/C Amplifier)
ACV ? (VSV for A/C Idle Up)
AF+ Air / Fuel Ratio Sensor - Bank 1 Sensor 1 - input to ECM
AF- ? (Air / Fuel Ratio Sensor - Bank 1 Sensor 1)
AF1+ Air / Fuel Ratio Sensor - Bank 1 Sensor 1 - input to ECM
AF1- ? (Air / Fuel Ratio Sensor - Bank 1 Sensor 1)
AFHT ? (Air / Fuel Ratio Sensor - Bank 1 Sensor 1)
AFL+ Air / Fuel Ratio input signal
AFL- ? (Air / Fuel Ratio Sensor - Bank 1 Sensor 1)
BATT Battery (constant voltage to ECM)
+B Battery power to ECM with ignition switch on
BK Brake / stoplight signal input
CCV ? (VSV for Canister Closed Valve)
CL+ ? (Throttle Control Motor; 2003+ with ETCS-i)
CL- ? (Throttle Control Motor; 2003+ with ETCS-i)
E1 ? (Ground)
E2 ? (Lines leading to Throttle Position Sensor)
E2G ? (Mass Air Flow; MAF)
E3 ? (Mass Air Flow; MAF)
EO1 ? (Ground)
EO2 ? (Ground)
EO3 ? (Ground)
EO4 ? (Ground)
EO5 ? (Ground)
EGR EGR cut control output
ELS ? (10A PANEL fuse, some years up through 2000)
ELS ? (10A TAIL fuse, 2001 onward)
EVG ? (Mass Air Flow, MAF)
EVP ? (VSV for Vapor Pressure Sensor - some 4-cyl's)
EVP ? (VSV for EVAP - some 4-cyl's)
EVP1 ? (VSV for EVAP - 2RZ, some 3RZ's, some 5VZ's)
EVP1 ? (VSV for Vapor Pressure Sensor - Some 5VZ's)
FC ? (Circuit Opening Relay)
FPU Fuel pressure up output
G ? (Distributor - 4 cyl)
G RPM signal from Camshaft Position Sensor
G+ RPM signal from Camshaft Position Sensor (5VZ)
G- ? (Distributor - 4 cyl)
G- ? (Camshaft Position Sensor - 4 cyl)
G2 RPM signal from Camshaft Position Sensor
G2+ RPM signal from Camshaft Position Sensor
GE01 ? (Lines tying into Throttle Control Motor circuit)
HAF1 ? (Air / Fuel Ratio Sensor - Bank 1 Sensor 1)
HAFL ? (Air / Fuel Ratio Sensor - Bank 1 Sensor 1)
HTAF1 ? (Air / Fuel Ratio Sensor - Bank 1 Sensor 1)
HT1 Heated O2 sensor heater control output
HT1B Heated O2 sensor heater control output - Bank 1 Sensor 2
HT2B Heated O2 sensor heater control output - Bank 1 Sensor 2
HT2 Heated O2 sensor heater control output
HTAF1 ? (Air / Fuel Ratio Sensor - Bank 1 Sensor 1)
HTS Heated O2 sensor heater control output - Bank 1 Sensor 2
IDL Throttle valve fully closed signal
IDLO ? (Cruise Control ECU / Actuator)
IGF ? (Igniter)
IGSW ? (7.5A IGN fuse)
IGSW ? (7.5A IGN fuse and Circuit Opening Relay)
IGT Ignition timing output to Igniter
IGT1 Ignition timing output to Igniter (5VZ)
IGT1 Ignition timing output to Igniter No. 1 (4-cyl)
IGT2 Ignition timing output to Igniter (5VZ)
IGT2 Ignition timing output to Igniter No. 2 (4-cyl)
IGT3 Ignition timing output to Igniter (5VZ)
IGT3 Ignition timing output to Igniter No. 3 (4-cyl)
IGT4 Ignition timing output to Igniter No. 4 (4-cyl)
KNK Knock sensor input
KNK1 Knock sensor input from Knock Sensor 1
KNK2 Knock sensor input from Knock Sensor 2
L4 Lo-4 / L4 Detection Switch
M+ ? (Throttle Control Motor; 2003+ with ETCS-i)
M- ? (Throttle Control Motor; 2003+ with ETCS-i)
ME01 ? (Ground)
MREL ? (EFI Relay)
NE RPM signal - Crankshaft Position Sensor
NE+ RPM signal - Crankshaft Position Sensor
NE- RPM signal - Crankshaft Position Sensor
NSW ? (Ignition switch / starter relay circuit)
OX1 Heated Oxygen Sensor input signal Bank 1 Sensor 1
OX1B Heated Oxygen Sensor input signal Bank 1 Sensor 2
OX2B Heated Oxygen Sensor input signal Bank 1 Sensor 2
OX2 Heated Oxygen Sensor input signal Bank 1 Sensor 2
OXS Heated Oxygen Sensor input signal Bank 1 Sensor 2
PRG ? (VSV for EVAP)
PSSW ? (Power Steering Oil Pressure Switch)
PSW ? (Power Steering Oil Pressure Switch)
PTNK ? (Vapor Pressure Sensor)
RSC ? (Idle Air Control Valve; IAC)
RSD ? (Idle Air Control Valve; IAC)
RSO ? (Idle Air Control Valve; IAC)
SDL ? (Data Link Connector 3; DLC3)
SIL ? (Data Link Connector 3; DLC3)
SP1 Vehicle speed sensor input
STA Starter (cranking) signal input
STA Clutch Start Switch or P/N Position Switch (some years)
STP Brake / stoplight signal input
TAC Tachometer connection
TBP ? (VSV for Pressure Switching Valve)
TC ? (Data Link Connector 3, DLC3)
TE1 ? (Data Link Connector 1; DLC1)
TFN ? (Detection Switch for Transfer / Neutral Position - 4WD)
THA Intake air temperature input from Intake Air Temp Sensor
THG ? (EGR Gas Temperature Sensor)
THW Engine coolant temperature Think of it as 'Temperature: Hot Water'
TPC ? (VSV for EVAP (some 2RZ's; some 5VZ's) )
TPC ? (VSV for Vapor Pressure Sensor (some 2RZ's, 3RZ, some 5VZ's))
TPC ? (Mass Air Flow meter; MAF (Some 5VZ's))
VC ? (Throttle position sensor)
VCC ? (Throttle position sensor)
VG Intake air volume from MAF
VPA ? (Accelerator Position Sensor; 2003+ with ETCS-i)
VPA2 ? (Accelerator Position Sensor; 2003+ with ETCS-i)
VTA Throttle valve opening angle
VTA2 ? (Throttle Position Sensor; 2003+ with ETCS-i)
W Malfunction Indicator Lamp; MIL; CEL indicator
WFSE ? (Data Link Connector 3, DLC3)