This collects, in one place, the terminal names and codes that appear across the notebook, so you can look one up without finding the page it came from. Every entry is from Mazda’s 2003 workshop manual (the pages are linked at the bottom). It is a lookup, not a wiring diagram: I haven’t recorded which way up each connector faces, so identify the connector and pin on Mazda’s diagram for your car.
PCM terminals
| Terminal | Circuit | What Mazda says | Where it’s used |
5X | Cooling fan relay No. 1 control | Pulled to 1.0 V or less when the fans are operating, battery voltage otherwise | Manual fan switch |
5AD | Cooling fan high-speed control (relays No. 2 and No. 3) | 1.0 V or less when running at high speed, battery voltage otherwise | Manual fan switch |
2W | OMP stepper coil No. 1 | Energised in the stepping sequence | How the OMP works |
2AB | OMP stepper coil No. 2 | As above | As above |
2V | OMP stepper coil No. 3 | As above | As above |
2Y | OMP stepper coil No. 4 | As above | As above |
2N | OMP position-switch signal | At idle, 1.0 V or less except at the maximum position, where it reads battery voltage | OMP diagnostics |
1U | OMP switch ground (sensor ground) | Continuity to switch terminal C | OMP diagnostics |
2AA | Ignition coil trigger, leading front (L/F) | | Coils and leads |
2AD | Ignition coil trigger, trailing front (T/F) | | As above |
2Z | Ignition coil trigger, leading rear (L/R) | | As above |
2AC | Ignition coil trigger, trailing rear (T/R) | | As above |
OMP connector pins
| Connector | Pin | Goes to |
| 6-pin (stepper) | C and D | Supply from the main relay (battery voltage with ignition on) |
| 6-pin | E | PCM 2W (coil No. 1) |
| 6-pin | F | PCM 2AB (coil No. 2) |
| 6-pin | A | PCM 2V (coil No. 3) |
| 6-pin | B | PCM 2Y (coil No. 4) |
| 3-pin (switch) | A | PCM 2N |
| 3-pin (switch) | C | PCM 1U |
Relays
| Relay | Job | Notes |
| Cooling fan relay No. 1 | Both fans low; also needed for high | Terminal A fed from the main relay, terminal E to PCM 5X |
| Cooling fan relays No. 2 and No. 3 | With No. 1, both fans high | Separate terminal-E wires joined into the 5AD wire |
| Fuel pump relay | Pump power | Engine-compartment relay |
| Fuel pump speed-control relay | Bypasses the pump resistor at high demand or cranking | Command with the FPRR PID |
Mazda’s relay layout figure (a left-hand-drive figure) numbers fan relay No. 1 as position 16, No. 2 as 19 and No. 3 as 13. I haven’t confirmed that layout on a UK RHD car.
Fault codes used in these notes
| Code | Mazda’s title | See |
P0480 | Cooling fan No. 1 control circuit problem (relay No. 1, 5X) | Manual fan switch |
P0481 | Cooling fan No. 2 control circuit problem (relays No. 2 and No. 3, 5AD) | As above |
P1686 | Metering oil pump control circuit, low flow side problem | OMP diagnostics |
P1687 | Metering oil pump control circuit, high flow side problem | As above |
P1688 | Metering oil pump control circuit, initial check problem | As above |
| PID | Meaning |
MOP_POS | The PCM’s current OMP step count. Read with a Mazda-capable tool such as Forscan; standard OBD-II readers won’t show it |
MOP_SW | State of the OMP position switch. Mazda describes it changing from on to off at 53 steps or over |
FPRR | Fuel-pump speed-control relay command |
Sources
Mazda RX-8 2003 workshop manual (European edition), read 2026-10-14 through a third-party mirror: PCM terminal inspection, OMP control operation, DTC P0480, DTC P0481, DTC P1686, P1687, P1688, fuel-pump speed-control operation and relay locations. The ignition-coil terminals are from Mazda’s US-style RX-8 service manual PCM terminal table.