DTC P0604 Control Module Random Access Memory (RAM). Chevrolet Chevy Suburban 4WD

For 1990-2009 cars only

Makes 🢒 Chevrolet 🢒 1998 🢒 Chevy Suburban 4WD - RHD 🢒 Engine 🢒 Engine Controls - 5.0L and 5.7L 🢒 DTC P0604 Control Module Random Access Memory (RAM)

VCM and EBCM - Figure
Engine Controls Schematics
OBD II Symbol Description Notice
Handling ESD Sensitive Parts Notice

Circuit Description

The control module contains memory in which incoming data can be temporarily stored. This is called random access memory (RAM). RAM is cleared and tested when the ignition is turned ON. If the data read from the memory locations does not match the data that was just stored to those locations during this testing, DTC P0604 will be set.

Conditions for Running the DTC

The ignition switch is in the RUN position.

Conditions for Setting the DTC

A difference was detected between the data read from a memory location and the data written to that location.

Action Taken When the DTC Sets

•	The VCM will illuminate the Malfunction Indicator Lamp (MIL) when the diagnostic runs and fails.

•	The VCM will record the operating conditions at the time the diagnostic fails. This information will be stored in the Freeze Frame and/or Failure Records.

Conditions for Clearing the MIL or DTC

•	The control module turns OFF the MIL after 3 consecutive drive trips when the test has run and passed.

•

A history DTC will clear if no fault conditions have been detected for 40 warm-up cycles. A warm-up cycle occurs when the coolant temperature has risen 22°C (40°F) from the startup coolant temperature and the engine coolant reaches a temperature that is more than 70°C (158°F) during the same ignition cycle.

•	Use a scan tool in order to clear the DTCs.

Test Description

The numbers below refer to the step numbers on the diagnostic table.

Replace the VCM even if this DTC exists only in history.

Step	Action	Value(s)	Yes	No
1	Important: Before clearing the DTCs, use the scan tool in order to record the Freeze Frame and the Failure Records for reference. This information will be lost when the Clear DTC Information function is used. Was the Powertrain On-Board Diagnostic (OBD) System Check performed?	--	Go to Step 2	Go to Powertrain On Board Diagnostic (OBD) System Check
2	Replace the VCM. Program the VCM. Refer to VCM Replacement/Programming . Perform the Crankshaft Variation Learn Procedure. Refer to Crankshaft Position System Variation Learn . Is the action complete?	--	Go to Step 3	--
3	Use the scan tool in order to select the DTC and the Clear DTC Information functions. Start the engine. Allow the engine to idle until normal operating temperature is reached. Select the DTC and the Clear DTC functions. Enter the DTC number which was set. Operate the vehicle within the conditions for setting this DTC as specified in the supporting text. Does the scan tool indicate that this diagnostic ran and passed?	--	Go to Step 4	Go to Step 2
4	Use the scan tool in order to display the Capture Info and the Review Capture Info functions. Are there any DTCs displayed that have not been diagnosed?	--	Go to the applicable DTC table	System OK