Introduction

IO93 is a bitmap parameter which operates according to OBD-II PIDs Service 01 PID 01 — Monitor Status Since DTCs Cleared.

Note: IO93 does not show exact OBD error codes. Instead, it reports whether the MIL light is on, how many diagnostic codes are flagged, and the availability/completeness of on-board readiness tests.

Warning: If you need to know exact OBD DTC codes, this feature is available via integration of the Ruptela device protocol, Command 9/109 Diagnostic Trouble Code on the server.

1 Overview

1.1 Parameter Structure

IO93 is a 4-byte (32-bit) value. Each byte (A, B, C, D) encodes specific diagnostic information:

Byte A — MIL status and DTC count
Byte B — Monitoring support flags and engine type
Byte C — Monitoring availability (varies by engine type)
Byte D — Monitoring readiness (varies by engine type)

1.2 Engine Type Abbreviations

SI — Spark Ignition (e.g. petrol/Otto or Wankel engines)
CI — Compression Ignition (e.g. diesel engines)

2 Byte Decoding Reference

2.1 Byte A — MIL and DTC Count (SI/CI)

Bit	Values	Description	Engine
`A0–A6`	0–127	Number of DTCs stored in the ECU	SI/CI
`A7`	0 = MIL OFF, 1 = MIL ON	Malfunction Indicator Lamp (MIL) status	SI/CI

2.2 Byte B — Monitoring Support and Engine Type

Bit	Values	Description	Engine
`B0`	0 = NO, 1 = YES	Misfire monitoring supported	SI/CI
`B1`	0 = NO, 1 = YES	Fuel system monitoring supported	SI/CI
`B2`	0 = NO, 1 = YES	Comprehensive component monitoring supported	SI/CI
`B3`	0 = SI, 1 = CI	Engine type (0 = Spark ignition, 1 = Compression ignition)	SI/CI
`B4`	0 = YES, 1 = NO	Misfire monitoring ready	SI/CI
`B5`	0 = YES, 1 = NO	Fuel system monitoring ready	SI/CI
`B6`	0 = YES, 1 = NO	Comprehensive component monitoring ready	SI/CI
`B7`	0	ISO/SAE reserved	SI/CI

2.3 Byte C — Monitoring Availability

Bit	Values	SI Description	CI Description
`C0`	0 = NO, 1 = YES	Catalyst monitoring supported	NMHC catalyst monitoring supported
`C1`	0 = NO, 1 = YES	Heated catalyst monitoring supported	NOx after-treatment monitoring supported
`C2`	0 = NO, 1 = YES	Evaporative system monitoring supported	ISO/SAE reserved
`C3`	0 = NO, 1 = YES	Secondary air system monitoring supported	Boost pressure system monitoring supported
`C4`	0	ISO/SAE reserved	ISO/SAE reserved
`C5`	0 = NO, 1 = YES	Oxygen sensor monitoring supported	Exhaust gas sensor monitoring supported
`C6`	0 = NO, 1 = YES	Oxygen sensor heater monitoring supported	PM filter monitoring supported
`C7`	0 = NO, 1 = YES	EGR and/or VVT system monitoring supported	EGR and/or VVT system monitoring supported

2.4 Byte D — Monitoring Readiness

Bit	Values	SI Description	CI Description
`D0`	0 = NO, 1 = YES	Catalyst monitoring ready	NMHC catalyst monitoring ready
`D1`	0 = NO, 1 = YES	Heated catalyst monitoring ready	NOx after-treatment monitoring ready
`D2`	0 = NO, 1 = YES	Evaporative system monitoring ready	ISO/SAE reserved
`D3`	0 = NO, 1 = YES	Secondary air system monitoring ready	Boost pressure system monitoring ready
`D4`	0	ISO/SAE reserved	ISO/SAE reserved
`D5`	0 = NO, 1 = YES	Oxygen sensor monitoring ready	Exhaust gas sensor monitoring ready
`D6`	0 = NO, 1 = YES	Oxygen sensor heater monitoring ready	PM filter monitoring ready
`D7`	0 = NO, 1 = YES	EGR and/or VVT system monitoring ready	EGR and/or VVT system monitoring ready

3 How to Decode IO93

3.1 Decoding Method

The best way to decode IO93 is to parse the value bit by bit. The recommended tool is Windows Calculator in Programmer mode, which provides a bit-toggle keypad for easy binary inspection.

Note: Decoding runs from MSB (most significant byte) to LSB (least significant byte). Because the parameter is 4 bytes long, prepend "0" as needed to ensure the full 32-bit length (bit count runs from 0 to 31.).

Windows Calculator in Programmer mode showing IO93 bit layout

3.2 Decoding Steps

Your device provides IO93 as a hexadecimal value. Follow these steps to decode it:

Take the hex value from the device.
Prepend "0" if needed to reach the full 32-bit length.
Convert to binary (use Calculator in Programmer mode).
Parse each byte (A, B, C, D) starting from bit A7 down to D0.
For each bit that is "1", refer to the reference tables above. For bits A0–A6, read the value as a number (a combination of bits give decimal number) — it indicates the DTC count.

4 Examples

4.1 Example 1 — `0x0D062040`

Convert the value step by step:

HEX:     0x0D062040 
Decimal: 218,505,280 
Binary:  0000 1101  0000 0110  0010 0000  0100 0000          
         [Byte A]   [Byte B]   [Byte C]   [Byte D]

Binary representation of 0x0D062040 in Calculator Programmer mode

Parse each byte starting from A7 down to D0:

Byte (HEX)	Decoded Meaning
`0D` (Byte A)	A7 = 0 → MIL/CEL is OFF A0–A6 = 13 → 13 DTCs currently stored
`06` (Byte B)	B1 = 1 → Fuel system monitoring supported B2 = 1 → Comprehensive component monitoring supported B3 = -0 → Engine type: SI (Spark Ignition)
`20` (Byte C)	C5 = 1 → Oxygen sensor monitoring supported (SI)
`40` (Byte D)	D6 = 1 → Oxygen sensor heater monitoring ready (SI)

4.2 Example 2 — `0x00080000`