2003 Saturn Ion Engine Coolant Light With Codes P0030 and P

PHILLYP

MEMBER
2003 SATURN ION
4 CYL
2WD
AUTOMATIC
95,000 MILES

Okay, before I start replacing parts, I want to make sure I am asking all the right questions. The "COOLANT" annunciator came on first, and about three hours later the check engine light came on. I checked the coolant level, and it was slightly low, but I did not see any leaks. I added coolant, and brought the car to auto zone to get the codes and they gave me the "H02S Bank 1 heater control circuit sensor 1 and 2 low." So, I started digging in my Haynes manual and noticed the coolant light is triggered by the Engine Coolant Temperature Sensor (ECT) which helps the Powertrain Control Module (PCM) control the air/fuel ratio. The upstream and downstream 02 sensors (both of which are causing the P0030 and P0036 codes) also help the PCM control the air/fuel ratio. So, is there one problem that could be casusing all three sensors to be acting up, or should I just bite the bullet and replace all three? Thanks

5 Replies

SATURNTECH9

MECHANIC
30,869 POSTS

First of all thank you so much for your donation. Your coolant light come's on when the coolant is low I wouldn't worry about your coolant temp sensor. Unless you have a code for it or your car is running bad. You could have just been low on coolant. As far as your code's go I could find those number's listed. Could you please have the code number's double checked for me so I can get you the correct information.I emailed you the engine code's list so you can see all the engine code's.I emailed them to your personal email. Let me know.

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Saturday, June 12th, 2010 AT 7:53 PM

PHILLYP

MEMBER
3 POSTS

Hey Louie, thanks for the fast response. To clarify, I have the P0031 AND P0037 codes. You don't think the "COOLANT" light is a concern? The light is still on (the resevoir is now full), and I noticed yesterday that the air conditioner took longer than usual to get cold, and while it was on, the car idled at very low RPMs. Thanks again

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Sunday, June 13th, 2010 AT 10:11 AM

SATURNTECH9

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I emailed to your personal email the trouble tree for your code's p0031 and p0037. Now on your coolant light does it say low coolant?Let me know.

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Sunday, June 13th, 2010 AT 9:58 PM

PHILLYP

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The light just says COOLANT and it comes on everytime I start my car. The coolant resevoir is full and I don't see any leaks. I am confused on this one. Thanks

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Monday, June 14th, 2010 AT 5:19 PM

SATURNTECH9

MECHANIC
30,869 POSTS

If the light stay's on all the time from the moment you start the car till you turn it off. Then let's do this go into the under hood fuse box with the key in the run position and take a test light and make sure the ERLS 10 amp fuse has power to each side of it. If it does then unplug the coolant bottle level sensor and jump the connector across the two terminal's connecting them together then start the car and see if the coolant display goes away. Let me know what you find.