P0731 to P0735: incorrect gear ratio codes

TSS friction discs for the 4F27E, 6F35 and RE4F03A transmissions

In short

With P0731 to P0735, the computer commanded a gear (1st to 5th) and measured a ratio that doesn't match: something is slipping or not applying in that gear.
A code tells you the gear; the combination of codes and your transmission's chart tell you the part: on the 6F35, P0733 with P0735 is the direct clutch; on the 5R55W, P0732 with P0735 is the overdrive band.
Many cars sold in Mexico don't use these codes: the 4L60E, the Cruze's 6T40, the Aveo, the Corolla and 4-speed Hondas have others for the same check.
It isn't always wear: makers also document speed sensors, fluid, software, mismatched tires and a low battery.
Neither an additive nor a fluid change repairs a slipping clutch, and clearing the code won't make it go away if the cause remains.

Codes P0731, P0732, P0733, P0734 and P0735 mean the transmission computer commanded a gear, from first to fifth, and measured a ratio that doesn't match: in practice, something is slipping or not applying. But each transmission builds each gear with different clutches and bands, and several brands don't even use these codes. Here's what each one means, which part it points to on your transmission, what causes them and how they're diagnosed.

What do P0731, P0732, P0733, P0734 and P0735 mean?

Code	What it means
P0730	Incorrect gear ratio, without saying which gear.
P0731	Incorrect ratio in 1st: the computer commanded first gear and didn't measure first gear's ratio.
P0732	Incorrect ratio in 2nd.
P0733	Incorrect ratio in 3rd.
P0734	Incorrect ratio in 4th.
P0735	Incorrect ratio in 5th.
P0729	Incorrect ratio in 6th.
P0736	Incorrect ratio in reverse.

The computer divides input speed (turbine speed) by output speed and compares it with the ratio of the gear it commanded; if it doesn't match for a set time, it stores the code. Honda, for example, sets it on its 5-speeds when the ratio is 20% above or 25% below that gear's ratio for 12 seconds, and Hyundai when the difference exceeds 200 rpm for more than a second. Nissan 4-speeds use engine speed instead of turbine speed.

Which transmissions don't use these codes?

Many cars sold in Mexico never set P0731 to P0734: they run the same check under other codes. That's why it pays to read them with a scan tool that reaches the transmission module.

GM 4L60E (Silverado, Tahoe, Suburban): P0751 and P0756, and P1870 or P0894 when it slips. More in our 4L60E guide.
GM 6T40 (Cruze, Sonic, Trax): one code per clutch: P2723 (1-2-3-4), P2714 (2-6), P0776 (3-5-R) and P0796 (4-5-6). More in our 6T40 guide.
Aveo (AW81-40LE): P0751, "no first or fourth gear".
Toyota Corolla: P0751 and P0756.
4-speed Hondas: only P0730.
Chrysler 46RE (Ram, Durango): P1740.
CVTs and dual-clutch units: on Nissan CVTs, P0730 means the belt is slipping, and newer ones use P17F0; Ford's PowerShift has its own codes.

They are used by Ford (4R70W, 5R55W, 4F27E, 6F35 and 6R80), Chrysler (41TE, 42RLE, 62TE and 45RFE), Nissan 4-speeds (Sentra, Tsuru and Tiida), 5-speed Hondas, Mazda, Hyundai and Kia, the Optra's ZF 4HP16 and VW's 09G.

Which part does each code point to?

A code tells you which gear has the fault; the combination of codes and the transmission's chart tell you which part. These are the cases the makers document:

Transmission	What each code or combination points to
6R80 (F-150, Lobo, Expedition, Mustang)	Ford names the clutches for each code: P0731 = clutch A or D; P0732 = A or C; P0733 = A or B; P0734 = A or E; P0735 = B or E; P0729 = C or E.
6F35 (Escape, Fusion)	P0733 with P0735 = the direct clutch or its solenoid (SSB): no 3rd or 5th. P0729, P0734 and P0735 together = the overdrive clutch or its solenoid (SSD): no 4th, 5th or 6th.
5R55W and 5R55S (Explorer)	P0732 with P0735 = the overdrive band, which works in 2nd and 5th. P0733 = the intermediate band, which works in 3rd.
4F27E (Focus, Mazda 3)	P0733 with P0734 = the direct (3-4) clutch, per a US Ford bulletin for the 2008 to 2011 Focus. P0732 with P0734 = the 2-4 band.
41TE and 42RLE (Caravan, PT Cruiser, Journey 2.4, Liberty)	1st = UD and L/R clutches; 2nd = UD and 2/4; 3rd = UD and OD; 4th = OD and 2/4. The clutch shared by the gears with codes is the suspect: 1st to 3rd, UD; 3rd and 4th, OD; 2nd and 4th, 2/4.
62TE (Town & Country, Journey V6)	Chrysler lists the clutches to check for each code; P0732 with P0735 point to the compounder's direct clutch (DC), which works in 2nd and 5th.
Sentra, Tsuru and Tiida (RE4F03)	Nissan checks shift solenoids A and B, the valve body and each clutch.
5-speed Honda (Civic 2006 to 2015, CR-V 2007 to 2014, Accord 2003 to 2012)	One clutch per gear: P0731 is the 1st clutch and its hydraulic circuit, P0732 the 2nd, and so on.
09G (Jetta 2.5)	P0729, P0734 and P0735 share the K2 clutch, which works in 4th, 5th and 6th; also check the solenoid modulator valve.
4-speed Hyundai and Kia (A4CF1)	P0731 = the speed sensors, the rear clutch (R/C) or the one-way clutch; P0733 = the sensors or the R/C, F/C or E/C clutches.

What causes these codes?

Almost always, a clutch or band that slips or doesn't apply: from wear, from low pressure (the pump, the valve body, a stuck valve) or from a solenoid that doesn't work properly. Nissan says it plainly: these codes aren't caused by an electrical fault but by a mechanical one, such as a stuck valve or a solenoid that doesn't operate properly. If the solenoid has an electrical fault, its circuit code sets instead, such as P0750 or P0755.

Is it always a damaged clutch?

No. Makers document other causes, and it's worth ruling them out before opening the transmission:

The speed sensors or their wiring: in the US, Ford tied P0731 with P0720 and P0722 to an output speed sensor fault in the 6R80 lead frame (2011 to 2014 F-150), and Hyundai lists the input and output sensors first.
Fluid level and condition: Mazda lists low or degraded fluid first.
Pressure: on the 62TE, Chrysler says loss-of-prime and line pressure sensor codes cause gear ratio errors.
Software or the wrong computer: in the US, Kia asked to verify the module part number for P0729, P0734 and P0735 on the 2014 Soul, and Chrysler fixed a P0732 with shudder with a reflash on 2007 models such as the Liberty, Wrangler, Ram 1500 and Durango.
Mismatched tires: Chrysler documented in the US that they can cause gear ratio codes, mainly on 4x4 and AWD vehicles.
A low battery: Nissan documented in the US a 2000 Sentra stuck in 3rd because of low voltage.
Codes with no symptoms: Nissan documented P0731, P0732 and P0733 with no drivability problem on 1995 to 1997 US Sentras.

Can I drive with code P0731?

Only as far as the shop. Many transmissions go into limp mode: the 62TE after four errors in the same drive; a 4-speed Hyundai holds 3rd, and the Optra's ZF 4HP16 holds 4th, per the manual of its US twin, the Suzuki Forenza. Ford warns the vehicle may go into neutral or hang in a gear, with the transmission light flashing. And if the transmission is slipping, driving on can damage that clutch further.

Note: on some units the check engine light doesn't come on. On Mazda Skyactiv units the computer locks out that gear, and on 5-speed Hondas such as the 2008 CR-V the D indicator blinks.

How is it diagnosed?

A scan tool that reaches the transmission module: the exact code, any other codes and freeze frame data. Repair the other codes first (speed sensors, pressure, solenoids): Ford, Toyota, Honda and Chrysler all say so.
Fluid level and condition, and leaks. In its US manuals, Honda drains the fluid through a strainer: if it shows metal debris or a lot of clutch material, it replaces the transmission.
The input and output speed sensors and their signal.
Line pressure and each clutch's pressure: if pressure is right and the gear slips, it's the clutch or band; if it's wrong, the pump or valve body.
The stall test, which isolates parts: on Nissan 4-speeds, if only 1st fails it's the low one-way clutch; if 3rd and 4th fail, the high clutch, and if 2nd and 4th fail, the band.
The solenoids and valve body: Nissan checks that each valve slides in its bore under its own weight.
Clear the code and road test: if it returns, Ford says to diagnose by symptom, and Honda and Ford then point to that gear's clutch.

Will an additive or a fluid change fix it?

No. A fluid change doesn't repair a slipping clutch, and Ford Mexico (2016 F-150) and Chrysler (2012 Journey) owner's manuals say not to add additives to the transmission because they can damage it.

How do you clear the code?

With a scan tool, after the repair. Clearing it fixes nothing: if the cause remains, the computer detects it again as soon as its conditions are met, sometimes in the same drive. Some transmissions turn the light off on their own after several fault-free starts, but the code stays in history. And after a repair, units such as Mazda Skyactiv or the 09G need a relearn with a scan tool.

TSS parts for these codes

These are the TSS parts for the components these codes point to most on each transmission:

Transmission	TSS parts
4F27E (Focus, Mazda 3)	friction discs and 2-4 (overdrive) band
5R55W and 5R55S (Explorer)	overdrive and intermediate band and friction discs
6F35 1st generation (2007 to 2012)	friction discs
6R80	steel discs and Red gasket kit
41TE, 42RLE and 62TE	overdrive, underdrive and reverse friction discs
62TE	low clutch drum
RE4F03A (Tsuru, Sentra)	friction discs
5-speed Honda (MAYA, MGHA, MGFA)	friction disc
09G	K2 clutch piston (4th, 5th and 6th)