PW1 ECU Technical Reference
Technical reference for the PW1 ECU, commonly found in D-series Honda applications such as the 1993 Concerto.
The PW1 ECU is a factory engine control unit typically found in Honda vehicles equipped with the D15B2 engine, such as the 1993 Honda Concerto.
Overview
The PW1 is an early-generation Honda ECU utilized for fuel and ignition management on SOHC D-series engines.
Note
Ensure your specific engine harness and sensor configuration match the PW1 pinout requirements before installation, as variations exist between regional market specifications.
Technical Specifications
- Engine Compatibility: D15B2
- OBD Standard: OBD1
- Common Applications: 1993 Honda Concerto
Diagnostic Resources
Use the following tools to assist with troubleshooting or wiring verification:
Wiring and Pinouts
For detailed signal mapping and component traces, refer to the standard OBD1 ECU wirelist structure.
IGP1
- Main Relay
IGP2
- Main Relay
No matching connections.
Resistor Color Code Reference
Use the color bands on through-hole resistors to identify their resistance value before installing ECU jumpers, pull-ups, voltage dividers, or sensor-scaling parts.
How to Read the Bands
| Resistor Type | Band 1 | Band 2 | Band 3 | Band 4 | Band 5 |
|---|---|---|---|---|---|
| 4-band | 1st digit | 2nd digit | Multiplier | Tolerance | - |
| 5-band | 1st digit | 2nd digit | 3rd digit | Multiplier | Tolerance |
Color Values
| Color | Digit | Multiplier | Tolerance |
|---|---|---|---|
| Black | 0 | x1 | - |
| Brown | 1 | x10 | +/- 1% |
| Red | 2 | x100 | +/- 2% |
| Orange | 3 | x1,000 | - |
| Yellow | 4 | x10,000 | - |
| Green | 5 | x100,000 | +/- 0.5% |
| Blue | 6 | x1,000,000 | +/- 0.25% |
| Violet | 7 | x10,000,000 | +/- 0.1% |
| Gray | 8 | x100,000,000 | +/- 0.05% |
| White | 9 | x1,000,000,000 | - |
| Gold | - | x0.1 | +/- 5% |
| Silver | - | x0.01 | +/- 10% |
| No band | - | - | +/- 20% |
Common ECU Examples
| Value | 4-Band Code | Typical Use |
|---|---|---|
| 220 ohm | Red, Red, Brown, Gold | LED/current-limiting or ECU hardware mods |
| 1k ohm | Brown, Black, Red, Gold | Pull-up, jumper, and driver-bias circuits |
| 1.2k ohm | Brown, Red, Red, Gold | Driver-bias circuits such as IACV repair references |
| 4.7k ohm | Yellow, Violet, Red, Gold | Transistor base resistor circuits |
| 10k ohm | Brown, Black, Orange, Gold | Pull-up, pull-down, and sensor-divider circuits |
Tip
Always confirm the measured value with a multimeter before soldering. Old ECU resistors can be heat-discolored, and some boards use small surface-mount parts marked with numeric codes instead of color bands.