Code P0734 and P0700 Hyundai Tuscon

2005 Hyundai TusconI went to auto zone for a scan on my 2005 Hyundai Tuscon 2wd with automatic transmission. The car was skipping and error code p0734 and code p0700 came up. I was told to replace speed sensors and change fluid does this sound right?


Start by inspecting the transmission fluid level and condition, and change fluid if necessary.

HYUNDAI Code P0734 – Fourth Gear Incorrect Ratio

P0734 is detected when A/T cannot be shifted to the 4th gear position even if electrical circuit is good.

Code P0734 Possible symptoms

– Engine Light ON (or Service Engine Soon Warning Light)
– Incorrect transmission shifting

P0734 Hyundai Description

This diagnosis monitors actual gear position by checking the torque converter slip ratio calculated by Transmission Control Module (TCM) as follows:

Torque converter slip ratio = A x C/B

A: Output shaft revolution signal from revolution sensor

B: Engine speed signal from Engine Control Module (ECM)

C: Gear ratio determined as gear position which TCM supposes

If the actual gear position is higher than the position (4th) supposed by TCM, the slip ratio will be more than normal. In case the ratio exceeds the specified value, TCM judges this diagnosis malfunction.

HYUNDAI Code P0700 – TCU Request For MIL On

Since the P0700 is just and informative code, check the TCM for more codes to resolve the problem.

Code P0700 Possible symptoms

– Engine Light ON (or Service Engine Soon Warning Light)
– Driveability problems
– Transmission shifting problems

Possible causes

– Shorted or open circuit within Transmission Control Module (TCM)
– Faulty Transmission Control Module (TCM)

 Hyundai Code P0700 Description

The Transmission Control Module (TCM) monitors the malfunction of sensors and actuators relating to transmission control. When the TCM detects a malfunction with the control, a signal is send to the Engine Control Module (ECM) to trigger the Engine Light or Service Engine Soon light. The ECM stores the P0700 code and it means the TCM detected a malfunction with the transmission controls.