← Back to list

1999 Jeep Cherokee P0740 OBD2 Code: TCC Malfunction & Misfire Symptoms

Model: 1999 Jeep Cherokee Fault Code: P0740 Posted: 2014-04-06 09:01

I own a 1999 Jeep Sport Cherokee with a 4.0L 6-cylinder engine and approximately 128,000 miles. A few months ago, I purchased the vehicle and immediately noticed OBD2 fault codes P0743 and P0740. Following forum advice, I performed a transmission fluid change, replaced the transmission filter, added T/A (torque converter) threadment, and installed an oil cooler. These steps resolved the torque converter slip issue and improved overall performance. However, the P0740 code persists, and occasionally, the vehicle exhibits symptoms such as engine misfire or pulling, especially under load. I'm seeking recommendations on how to resolve this remaining issue. Any insight into potential causes related to transmission control or engine management would be greatly appreciated. Thank you, Juan

Related fault codes
P0740
Comments (5)
Anonymous 2014-04-06 09:18

I'm short on time, but wanted to ask — did you use the correct transmission fluid? Universal or incorrect types won't work for this model. Also, your last sentence is a bit unclear: 'still P0740 code and occasionally appear a symptom as misfire or pulled' — could you clarify what you mean by that?

Anonymous 2014-04-06 09:43

You're referring to the OBD2 P0740 code, which indicates a 'Torque Converter Clutch (TCC) Malfunction'. This code remains active. Additionally, the vehicle occasionally experiences engine misfire symptoms, and I've noticed two instances of P1391 — a crankshaft or camshaft-related trouble code.

Anonymous 2014-04-06 09:54

What transmission fluid did you use? I believe it should be ATF-4. Nothing else will work for this application. We can address older codes later, but the TCC function is critical here.

Anonymous 2014-04-06 10:00

I believe the mechanic used the correct fluid because he has extensive experience working on Jeep Cherokees and frequently handles these models.

Anonymous 2014-04-06 12:30

Assuming ATF-4 was used, let's stay positive — you've already resolved P0743 and another code with a fluid and filter change. What additive did you use? It might be worth considering an additive to improve TCC fluid flow. Also, ensure the vehicle’s stock components are intact — temperature, RPM, MAP, and TPS sensors all play a role in enabling proper TCC operation. Suggestion: Clear the P0740 code when it resets. Then check the freeze frame data to see if any related codes like P1696 or P0320 appear simultaneously.