Common Cadillac CTS Problems: 1st Generation 2003 to 2007

Mechanic showing Cadillac CTS Problems

The first-generation Cadillac CTS was designed and built to replace the Cadillac Catera. It was the first car from Cadillac to offer a manual transmission since 1988. GM built each trim with one of six engine options that were paired with either a five-speed or six-speed automatic or manual transmission. Like every car, the CTS has its own issues. Here is a list of the top 5 Cadillac CTS problems that we’ve come across. 

1. EVAP Purge Solenoid

Purge valve

The EVAP is a system that helps to contain fuel vapors inside the gas tank. It prevents them from leaking into the environment and causing pollution. The system uses an EVAP purge solenoid to create a vacuum that helps it to work. When you get a check engine light that generates the codes P0496, P0441, or P0443; the solenoid could be stuck closed or open. 

It could also be that its electronic components have failed to function. You’ll need to replace it to get rid of the codes. You can find your EVAP purge solenoid on the top left corner of the engine once you remove the cover. Expect to pay anywhere between $60 and $75 for the part. 

Something else that could generate the EVAP codes is a gas cap that is loose. Check if you forgot to close it tightly during your last fuel refill. You can also take a look at the seal for any cracks and tears. When closing it, make sure the ratchet feels tight. Replace the gas cap if you notice any issues with how it closes. 

2. No Start Issues

Scanner monitoring data to diagnose a no start issue

One of the most common Cadillac CTS problems that owners experience when they get into the car is hearing nothing at all when they turn the key. Normally, you should hear a click or the sound of the engine turning. When this doesn’t happens, you’ll want to start checking the basics. 

First, ensure your battery terminals are tight and not corroded. Second, test the starter and all the fuses using a test light to make sure they are good. If you have a scan tool with you, hook it up to the PCM or ECM. You’re most likely not going to get any communication from the system if the PCM is internally bad. It could be that the connections are loose or that there’s no power and ground. If that’s the case, you’ll need to replace the PCM. 

Another common no start issue is hearing the engine turn over but the vehicle never starts. What you can do in this case is hook up a scan tool with a screen so that you get to see the RPMs. If it reads zero, chances are the crank sensor is bad. You can find the sensor underneath the vehicle and on the backside of the motor in your Cadillac CTS. 

A bad crank sensor can also cause the car to suddenly stall after it has been warmed up for a while. If you go to start it, you’ll only hear several cranks. The car only starts when you let it cool down completely. Also, if you ever hear a funny sound when starting it, something could be wrong with the timing chains or timing belts. 

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3. Timing Belts and Timing Chains

Timing belt location on a 03-07 Cadillac CTS

As mentioned earlier, Cadillac offered the CTS with six different engines. Depending on the trim you picked, your car could either have timing belts or timing chains. If you use the former for too long without changing them, they could break. The chains end up stretching and causing other problems. 

The belts on the Cadillac CTS have an external cover at the front while the chains are attached to the valve cover. Both connect the crankshafts to the camshafts. The crankshafts are connected to the pistons and can be found at the bottom of the engine compartment. The camshafts are located up top. 

When your timing chains or timing belts break or stretch, your vehicle’s engine parts will not move in synchrony. This can cause a number of issues including an engine that runs poorly. 

4. Engine Misfires

Reading oil level on a dipstick

If you have a check engine light, a P0300 code, or an engine that is running rough; it means that one or more of your cylinders are misfiring. This is one of the Cadillac CTS problems that are relatively easy to diagnose. 

You can start by checking the oil level. Sometimes, these vehicles tend to burn a little bit of oil and people neglect to check them. When the oil runs low, most of the internal engine components will not work properly. These include the timing chain tensioners, the camshaft solenoids, and the lifters. 

If you check your oil and realize that it is down to the base of the hash marks provided on the dipstick, you’ll need to add about a quart of oil to bring it back to par. If it’s way below that or not even on the stick, you’ll need 2 or 3 quarts. It’s always best to change the oil completely and monitor it regularly. Other Cadillac CTS problems that could cause an engine to misfire include bad spark plugs and bad coils. 

5. Coolant Thermostat

Monitoring a coolant thermostat with a borescope camera

The first thing you’ll get when you have a problem with the coolant thermostat is a check engine light. When you scan it, you’ll get a P0128 code which translates to “coolant thermostat below threshold.” 

The PCM is always monitoring the temperature of the engine coolant. If the thermostat gets stuck open and the temperature falls below 210 degrees (to about 175), the PCM activates the check engine light. 

If you have the Cadillac CTS that runs on the V6 engine, getting to the coolant thermostat is not easy. It’s located on the backside of the engine. You’ll need to take the battery out, the battery tray, and part of the cowl to access it. 

If your CTS runs on the 6.0-liter LS2 V8 engine, you’ll find the thermostat located right in front of the engine. This is one of those Cadillac CTS problems that can be a major pain to take care of. Remember to replace the thermostat together with its housing. 

Fix Cadillac CTS Problems Yourself

Find many repair videos for the 1st gen 03-07 Cadillac CTS in 1A Auto’s how-to video library.

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Top 5 Cadillac CTS Problems - 1st Gen (2003 to 2007) - 1A Auto
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Top 5 Cadillac CTS Problems - 1st Gen (2003 to 2007) - 1A Auto
Like every car, the CTS has its own issues. Here is a list of the top 5 Cadillac CTS problems that we’ve come across.
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1A Auto
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