Bonk DTC docs
33-01 Strongly inferred

ECM internal memory fault (33-01)

The ECU reported a problem with its own internal memory. Present on the 2005-2006 CBR600RR onward.

Manufacturer
Honda
Platform
PGM-FI (Keihin, Renesas M32R)
Models
CBR600RR
Years
2005-2022
Subsystem
ECM internal memory
FI-light blink
3 long, 3 short
Hex
0x3301
Saw 33-01 as 3 long, 3 short on the FI light? Decode a blink pattern →
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Strongly inferred. Strongly inferred: the standard Honda meaning is well established, but exactly how this ECU handles it internally is inferred rather than fully confirmed.

What it means

The ECU stores fault codes and settings in its own internal memory and checks that memory is readable and consistent. This code sets when that internal check fails. It is an internal fault, not something you can probe in the wiring harness.

Conditions

Detection conditions

  • The ECU’s internal memory self-check finds a problem.

Sets the fault when

  • The internal memory check reports an error.

Clears the fault when

  • Fix the underlying problem, then clear the stored codes with a diagnostic tool or the manufacturer’s reset procedure. If the fault is still present, the code returns the next time the ECU detects it.

Parts involved

  • ECU internal memory (not externally serviceable)

Symptoms & likely causes

Possible symptoms

  • FI (check-engine) light on
  • Stored codes or settings may not save correctly

Likely causes

  • Failing internal ECU memory
  • Internal ECU fault
  • Corrupted stored data

Diagnostic guidance

If this persists after clearing, the ECU itself is the suspect, as it is an internal fault.

How the ECU decides

A simplified view of the logic behind this code: a short C snippet with a plain-English summary. It shows the real decision the ECU makes without the low-level detail.

When the ECU confirms a fault, it saves the code and turns on the FI (check-engine) light. For a serious fault it also runs the engine on safe default values (limp-home) so you can still ride, with the light on.

C How a confirmed fault is stored 
// Once a fault is confirmed, remember it and warn the rider.
if (fault_confirmed) {
    store_code(code);      // kept until the codes are cleared
    fi_light = ON;
    if (fault_is_serious)
        limp_home = ON;    // safe defaults so you can ride home
}
Reverse-engineered interpretation · CBR600RR ECU reverse-engineering analysis

Questions about code 33-01

What does Honda code 33-01 mean?
The ECU reported a problem with its own internal memory. Present on the 2005-2006 CBR600RR onward.
Which motorcycles does code 33-01 apply to?
It is documented here for the Honda CBR600RR (2005-2022). Other Honda models may use the same display code with a different meaning, so confirm against your model.
Can I still ride with code 33-01?
It depends on the fault. Code 33-01 relates to the ECM internal memory. If the bike runs poorly or a safety-related system is affected, avoid riding until it is checked. The FI light stays on until the fault is fixed and the codes are cleared.
What should I check first for code 33-01?
If this persists after clearing, the ECU itself is the suspect, as it is an internal fault.

Sources

Every technical claim on this page traces to the research below. Source labels are sanitized; no local research paths are exposed.

  • firmware

    2005-2006 Honda CBR600RR ECU firmware

    Factory PGM-FI firmware for the 2005-2006 CBR600RR. Primary source of truth.

  • analysis

    Firmware fault-code table extraction

    Reads the list of codes the ECU can store directly out of each firmware.

  • reference

    HondaECU project (open-source Honda ECU tool)

    Community reference mapping Honda PGM-FI codes to their meanings.

  • analysis

    CBR600RR ECU reverse-engineering analysis

    Independent analysis of how the ECU detects, stores, and reports faults.

Content version 1.0.0 · last reviewed 2026-07-14

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