Prelude L4-1958cc SOHC (1988)
Voltage Signal: Description and Operation
1988 Prelude
1.
Connect system checker harness between ECU and connector, Fig. 23.
2.
Turn ignition switch to On position and measure voltage between B18 (+) terminal and A18 (-) terminal.
3.
If battery voltage is not available, proceed to step 7.
4.
If battery voltage is available, disconnect 2 pin connector on power steering oil pressure switch and connect blue/red terminal to black terminal.
5.
If battery voltage is not available, replace power steering oil pressure switch.
6.
If battery voltage is available, repair open in blue/red wire between ECU terminal B18 and power steering oil pressure switch or black wire
between power steering oil pressure switch and ground 301.
7.
If battery voltage was not available in step 3, start engine, turn steering wheel slowly and measure voltage between B18 (+) terminal and A18 (-)
terminal while steering wheel is turning.
8.
If battery voltage is not available, disconnect B connector from engine compartment wiring harness only, not the ECU.
9.
If battery voltage is not available, substitute known good ECU and repeat test and, if battery voltage is now available, replace original ECU.
10.
If battery voltage is available reconnect B connector to engine compartment wiring harness and disconnect 2 pin connector from power steering oil
pressure switch.
11.
If battery voltage is available, replace power steering oil pressure switch.
12.
If battery voltage is not available, repair short in blue/red wire between ECU terminal B18 and the power steering oil pressure switch.