What does fault code P0604 mean?

The control module has detected a fault in the Internal Control Module Random Access Memory (RAM) Error (P0604). The underlying code points specifically at working memory (RAM). Measurements: • Internal Control Module Random Access Memory (RAM) Error – Permanent B+ Supply (Voltage (V)): 12.4 - 12.7 V (ignition OFF) / 13.5 - 14.7 V (engine running) [Condition: At module supply pins] • Internal Control Module Random Access Memory (RAM) Error – Ignition-Switched Supply (Voltage (V)): 11.8 - 14.4 V [Condition: Ignition ON] • Internal Control Module Random Access Memory (RAM) Error – Ground Connections Voltage Drop (Voltage (V)): < 0.1 V per ground point [Condition: Under load to battery negative] • Internal Control Module Random Access Memory (RAM) Error – 5 V Reference Outputs (Voltage (V)): 4.95 - 5.05 V per circuit [Condition: Ignition ON, sensors unplugged one at a time] Oscilloscope: Log module supply voltage during cranking and load changes. It must not fall below 9.5 V on start or carry high-frequency noise that disturbs the processor. (Scale: 500 ms/div, 5 V/div)

What are the symptoms of fault code P0604?

Short to battery voltage causes signal over-voltage condition Check Engine Light (MIL) illuminated Possible drivability or power reduction Risk of failing an emissions inspection

What causes fault code P0604?

Most likely: Voltage disturbance or a marginal internal memory cell — often triggered by a poor ground or charging fault Most likely: Open circuit on signal wire, spread terminal pin, or short to power feed at Internal Control Module Random Access Memory (RAM) Error Likely: Chafed or pinched wiring harness along the signal path to Internal Control Module Random Access Memory (RAM) Error Likely: Poor ground connection or excessive voltage drop (> 0.1 V) at the ground point for Internal Control Module Random Access Memory (RAM) Error Rare: Defective internal output driver or reference circuit in the control module for Internal Control Module Random Access Memory (RAM) Error

How do you fix fault code P0604?

Check the module supply and grounds under load (voltage drop < 0.1 V) and clear the code; if it returns, the processor board is internally faulty. Verify no voltage cross-talk or short to adjacent 12V power feeds within the wire harness. Verify loaded supply voltage and harness terminal pins at Internal Control Module Random Access Memory (RAM) Error. Check circuit continuity and ground-side voltage drop (< 0.05 V) for Internal Control Module Random Access Memory (RAM) Error. Inspect module enclosure and connector headers for water ingress, fretting corrosion, or PCB thermal damage. Mechanic tip: RAM codes are often one-off events after a voltage glitch — log whether it recurs before condemning the module.

Standard EOBD

P0604 - Intern styreenhetsfeil – RAM-minne

Q: What are the symptoms of fault code P0604?

Short to battery voltage causes signal over-voltage condition Check Engine Light (MIL) illuminated Possible drivability or power reduction Risk of failing an emissions inspection

Q: What causes fault code P0604?

Most likely: Voltage disturbance or a marginal internal memory cell — often triggered by a poor ground or charging fault Most likely: Open circuit on signal wire, spread terminal pin, or short to power feed at Internal Control Module Random Access Memory (RAM) Error Likely: Chafed or pinched wiring harness along the signal path to Internal Control Module Random Access Memory (RAM) Error Likely: Poor ground connection or excessive voltage drop (> 0.1 V) at the ground point for Internal Control Module Random Access Memory (RAM) Error Rare: Defective internal output driver or reference circuit in the control module for Internal Control Module Random Access Memory (RAM) Error

Relatert:Intern styreenhetsfeil, Ledningsnett og kontakter, Styreenhet (ECM/PCM)

System

Drivlinje (Motor og girkasse)

Kontakt oss Finn reparasjon

Teknisk beskrivelse

Styreenheten registrerer en feil i Intern styreenhetsfeil (P0604). Koden peker spesifikt på arbeidsminne (RAM).

Multimeter Målepunkter & Nominelle Verdier

Målepunkt / Komponent	Måletype	Nominelt Målområde	Målevilkår
Intern styreenhetsfeil – permanent matespenning	Spenning (V)	12.4 - 12.7 V / 13.5 - 14.7 V	Ved modulens pinner
Intern styreenhetsfeil – jordforbindelser spenningsfall	Spenning (V)	< 0.1 V	Under belastning

Intern styreenhetsfeil – permanent matespenningSpenning (V)

Børverdi:12.4 - 12.7 V / 13.5 - 14.7 V

Ved modulens pinner

Intern styreenhetsfeil – jordforbindelser spenningsfallSpenning (V)

Børverdi:< 0.1 V

Under belastning

Oscilloskop Kurveformanalyse

500 ms/div, 5 V/div

Logg matespenningen under start; må ikke falle under 9.5 V.

Mulige årsaker

Spenningsforstyrrelse eller marginal minnecelle

Brudd i signalledningen, løst kontaktpunkt eller kortslutning til pluss ved Intern styreenhetsfeil

Gnagd eller klemt ledningsnett fram til Intern styreenhetsfeil

Dårlig jordforbindelse eller spenningsfall (> 0.1 V) for Intern styreenhetsfeil

Defekt driver eller referanseutgang i styreenheten for Intern styreenhetsfeil

Symptomer

Kortslutning mot pluss gir overspenning i kretsen

Motorlampe (MIL) lyser

Mulig redusert kjørbarhet eller effekt

Risiko for underkjent EU-kontroll

Anbefalt tiltak

Kontroller matning og jord under belastning; kommer koden tilbake er kortet defekt.

Kontroller at det ikke er overslag fra 12V-ledninger i kabelbunten.

Sjekk matespenning og kontaktstykke ved Intern styreenhetsfeil.

Mål kontinuitet og jordspenningsfall (< 0.05 V) for Intern styreenhetsfeil.

Sjekk kontaktdon og kretskort for fukt og korrosjon.

Mekanikerens tips

RAM-koder er ofte engangshendelser.

Relaterte feilkoder

P060C

Intern styreenhetsfeil Main Processor – urimelig verdi

P064C

Glødepluggstyreenhet (GPCM) 1

P0652

sensor referansespenning 'B' – lavt signal

P067B

Sylinder 4 Glødeplugg – styrekrets høyt signal

Målepunkt / Komponent

Måletype

Nominelt Målområde

Målevilkår

Intern styreenhetsfeil – permanent matespenning

Spenning (V)

12.4 - 12.7 V / 13.5 - 14.7 V

Ved modulens pinner

Intern styreenhetsfeil – jordforbindelser spenningsfall

Spenning (V)

< 0.1 V

Under belastning