I have a 2007 Saturn Vue Hybrid 2.4L, the low coolant light comes on almost instantly and stays on even though there is plenty of fluid in the reservoir. I've drained and replaced the coolant recently. The check engine light will come on and I can usually clear it with a scanner/reader but the low coolant always stays on and the check engine light always comes back on eventually. There are times I start the car and there's a a noise near the front of the car that sounds like something is hitting the fan and then stops doesn't last more than 5 min max. It has thrown the codes;
B3844 -Engine Coolant Circulation Pump Circuit
P0A06-Drive Motor Control Module Coolant Pump 1 Relay Control Circuit Low Voltage

I've been trying to figure out what would be the cause;
-coolant temp sensor
-low coolant sensor
-water pump
-auxillary water pump

The car does seem to struggle to shift at times but no smoke coming from the exhaust, the cars AC and heat are working fine, one thing the car seems to have done for a while before the low coolant light the engine fan is ALWAYS on.

 

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Home >> Saturn Truck >> 2007 >> VUE FWD L4-2.4L Hybrid >> Repair and Diagnosis >> A L L Diagnostic Trouble Codes ( DTC ) >> Testing and Inspection >> P Code Charts >> P0A06

P0A06

DTC P0A06 or P0A07

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Initial Inspection and Diagnostic Overview
* Review Strategy Based Diagnosis for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptor

DTC P0A06
- Starter/Generator Control Module Coolant Pump Control Circuit High Voltage

DTC P0A07
- Starter/Generator Control Module Coolant Pump Control Circuit Low Voltage

Diagnostic Fault Information

Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Initial Inspection and Diagnostic Overview

Circuit/System Description

The starter/generator control module (SGCM) monitors the coolant pump control circuit for an open wire or a over current condition.

Conditions for Running the DTC

The engine is running.

Conditions for Setting the DTC

P0A06

Eco-back signal (High) does not match to the LSD output signal for 320 ms.

P0A07

Eco-back signal (Low) does not match to the LSD output signal for 320 ms.

Action Taken When the DTC Sets

P0A06, P0A07

Set engine coolant pump validity to invalid.

Conditions for Clearing the DTC

P0A06
* LSD over current fault removed.
* Clears 30 seconds after cycle wakeup signal.

P0A07
* LSD wire open fault removed.
* Normal range for 3.5 seconds.

Diagnostic Aids

P0A06

Possible over current or wire short to power line fault.

P0A07

Possible wire open or short to ground fault.

Circuit/System Verification

Caution: To help avoid personal injury, be careful when working in the vicinity of the generator battery disconnect control module. Internal components will still be live, 36V potential, even when the cover has been opened or removed.

1. Ignition ON, command the SGCM coolant pump ON and OFF with a scan tool.
2. Observe the operation of SGCM coolant pump.

Circuit/System Testing

P0A06
1. Ignition OFF, disconnect the harness connector at the SGCM coolant pump.
2. Ignition ON, verify that a test lamp illuminates between the control circuit terminal 1 and ground.

• If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the SGCM.

P0A07
1. Ignition OFF, disconnect the harness connector at the SGCM coolant pump.
2. Ignition ON, verify that a test lamp illuminates between the B+ circuit terminal 2 and control circuit terminal 1.

• If the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the SGCM.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure. Verification Tests

Control Module References for SGCM replacement, setup, and programming.


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Does in fact sound like a control module issue.
I believe the fan being on all the time is a failsafe for the cooling system because it's no longer clear to the PCM if the coolant pump is running or not. Doesn't mean it will keep from overheating but it's the best it can do if the coolant is not circulating..