~9/30/22 LH2.4 bench test results
HYB = Thick Film Hybrid, 40-pin
ECU = LH ECU 35-pin connector
MCU = 80C535 Microcontroller, 68-pin PLCC pkg
Measured with Bosch 0280000937 ECU (B230FT non-egr and 12.0V bench supply
Pin Notes To/From
--- ---------------------------------- --------------------------------------
Power/Ground
------------
HYB-9 +12V
HYB-12 +5V
HYB-31 +5V (LH2.4 this may be a tied-off input instead of power pin)
HYB-35 +5V
HYB-10 GND
HYB-13 GND
HYB-20 GND
HYB-1 4.06v voltage reference output n/c
Unused?
-------
HYB-4 LH2.4 n/c
- LH2.4 stays at ~12v
HYB-5 LH2.4 n/c
- LH2.4 stays at ~5v
HYB-40 LH2.4 MCU-6/P4.4
- LH2.4 stays at ~0v
RPM, Reset and Fuel Pump Related
--------------------------------
HYB-6 LH2.4 RPM input ECU-1
- RPM input from EZK, 0.6v to 9.7v
HYB-29 LH2.4 ezk rpm out to cpu MCU-36/P1.0
- RPM output, 5v to 0v (inverting from HYB-6)
HYB-34 something to do with rpm n/c
- 4v at 0rpm, negative sawtooth at rising rpm edge, 4v down to 0.9v
HYB-37 LH2.4 mcu/sram reset pin MCU-10/RESET
HYB-39 LH2.4 watchdog reset from software? MCU-25/P3.4
- goes to 5v for ~50ms after powerup, then changes to ~1kHz square wave
HYB-38 LH2.4 ??? n/c
- low level signal with ~1khz/1ms tiny noisy square wave
HYB-2 LH2.4 RPM OK status to MCU? MCU-8/P4.6
- goes from 0v to 4.9v ~100us after first rising EZK RPM edge, goes to 0v ~0.77sec after RPM stops
(RPM from EZK stops high then goes low after ~0.73sec, HYB-2 goes low ~38ms later)
HYB-3 LH2.4 fuel pump relay output ECU-20 (after T302 and CA3272 driver)
- 10.2v 0rpm / 0.5v 800rpm
fuel pump turns on ~100uS after first rising EZK RPM edge, or ~0us after first falling RPM edge to MCU
fuel pump turns on ~50us after rising reset when RPM running, or on for ~1 second after power-on reset no RPM
fuel pump turns on after HYB-39 goes to 1kHz, then primes for ~1 second before going off
fuel pump turns off ~1 second after rpm goes to 0
look like fuel pump may be directly controlled by hybrid without any PumpOn MCU output signal
Idle Air Control Related
------------------------
HYB-32 LH2.4 iac out to drive transistor T301-B (middle power transistor)
- 0v 0rpm / ~0.7v peak pulses 800+ rpm, PWM
HYB-17 LH2.4 iac_in input from ECU pin ECU-33
- IAC 0v to 12v PWM
HYB-22 LH2.4 iac in ? MCU-1/P4.0
- 0v when HYB-17 12v, 5v when HYB-17 0v
HYB-33 LH2.4 iac in? MCU-34/P1.2
- 5v when HYB-17 12v / 0v when HYB-17 0v, pulse width is ~60% of HYB-22 at 0rpm, same PW at higher RPM
O2 Sensor Related
-----------------
HYB-11 LH2.4 O2 sensor input ECU-24
- O2 sensor input, benchtop switch gives: 0.1v/0.45v/0.9v
HYB-27 LH2.4 lambda rich1 MCU-29/P1.7
- 0v = rich, O2 > 0.60v / 5v = not rich, O2 < 0.5v
HYB-28 LH2.4 lambda rich2 MCU-30/P1.6
- 0v = rich, O2 > 0.68v / 5v = not rich, O2 < 0.59v
5v - 12v Translation
--------------------
HYB-7 AC switch on input ECU-15
- 0v ac off / 9.6v ac on
HYB-36 LH2.4 ac switch on output MCU-64/P5.3
- 5v ac off / 0v ac on
HYB-14 LH2.4 Auto PN switch input ECU-30
- 2v PN / 11.3v D
HYB-24 LH2.4 Auto PN switch output MCU-65/P5.2
- 5v PN / 0v D
HYB-8 TXD diagnostics input MCU-22/P3.1
- Diag box LED - LED turns on when low, 4.7v to 0v
HYB-30 LH2.4 TXD diagnostics in/out ECU-12 obd box socket 2
- Diag box socket 2 - 12v normally, 0v when button pushed or LED on
HYB-19 LH2.4 TPS IDLE input ECU-2
- 0v IDLE, 11v cruise
HYB-21 LH2.4 TPS IDLE output MCU-67/P5.0
- 5v IDLE, 0v cruise
HYB-15 LH2.4 TPS WOT input ECU-3
- 0v WOT, 12v cruise
HYB-26 LH2.4 TPS WOT output MCU-66/P5.1
- 5v WOT, 0v cruise
HYB-16 LH2.4 Knock enrichment input ECU-28
- 0.9v 0rpm / 7.3v 800rpm+
HYB-25 LH2.4 Knock enrichment output MCU-61/P5.6
- 5v 0rpm, 0v 800rpm+
HYB-18 LH2.4 AC clutch on input ECU-14
- 0v off / 11.4v on
HYB-23 LH2.4 AC clutch on output MCU-62/P5.5
- 0v off / 5v on
BS301/CA3272 600mA driver chip connections:
- ECU-10 is low speed fan output, from BS301/CA3272-2 OutA, InA-28 from MCU-23/P3.2
- ECU-11 is high speed fan output, from BS301/CA3272-4 OutB, InB-27 from MCU-24/P3.3
- ECU-31 is ?, from BS301/CA3272-12 OutC, InC-17 from MCU-2/P4.1
- ECU-20 is fuel pump relay output, from BS301/CA3272-14 OutD, InD-16 from T302-C, from HYB-3
(and yes, the ECU-19 coding plug goes through a resistor divider to MCU-14/P6.6/AN6)