Can I keep driving with P0700?

Only if shifts are smooth and there's no slipping. If the truck is stuck in limp mode or shifts violently, get it home and stop driving until diagnosed.

Will a transmission flush fix P0700?

A flush can sometimes mask the symptom by freeing stuck solenoids, but it often makes things worse by dislodging debris into the valve body. Drain and refill only, never a power flush, on a high-mileage truck.

What's the difference between P0700 and P0701?

P0700 is generic (any TCM fault). P0701 is range/performance — TCM commanded a shift but the gear ratio came back wrong. P0701 always indicates internal slippage.

Can a bad battery cause P0700?

Yes. Low voltage during cranking can corrupt TCM data and trigger spurious P0700. Always load-test the battery before chasing trans codes.

P0700

Transmission Control System Malfunction

MODERATE

SystemTransmission

Difficulty

Cost$100–$3500

Read10 min

What It Means Symptoms Common Causes Diagnosis Steps How to Fix It Emissions Test?Repair Cost FAQs

By Mike Reeves

ASE Master Technician (L1 Advanced Engine Performance) · 18 yrs

Technically reviewed by Sara Lopez

Last updated June 11, 2026

What Does P0700 Mean?

P0700 is a generic 'transmission control system malfunction' code. By itself it tells you nothing about what's wrong — it just informs the engine ECM that the TCM (transmission control module) has stored its own code. To diagnose, you must pull TCM-specific codes (P07XX, P08XX) using a transmission-capable scanner.

On the 2009–2020 Dodge Ram 1500 with the 545RFE or 8HP70 transmission, P0700 most often accompanies P0731–P0736 (gear ratio errors), P0740 (TCC), or P0868 (line pressure). The underlying issues range from a $25 solenoid to a $4000 rebuild.

Symptoms

Check engine light + transmission warning

Combined indicators on dash.

Harsh or delayed shifts

TCM is in 'limp mode' — locks transmission in one gear.

Stuck in 2nd or 3rd gear

Common failsafe — drive home only.

Slipping or flaring shifts

Internal hydraulic problem.

No reverse or no forward

Worst case — internal mechanical damage.

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Common Causes

1.Low/dirty/burnt transmission fluid
30%
Always check first. Burnt fluid means internal damage already started.
2.Failed shift solenoid
25%
545RFE solenoid pack is a known failure point ~120k miles.
3.TCM electrical fault (wiring, connector)
15%
Corrosion at TCM connector; chafed harness near transmission.
4.Worn clutch packs / band
15%
High mileage failure. Confirm via pressure test before rebuild quote.
5.Failed TCM
8%
Software corruption or hardware failure. Reflash before replacing.
6.Bad input/output speed sensor
7%
Sensor failure mimics gear ratio errors.

Step-by-Step Diagnosis

Pull all codes from BOTH modules

Use a scanner that reads TCM codes, not just ECM. Cheap OBD-II tools won't show transmission DTCs. Look for P073X (ratio errors), P074X (TCC), P075X-077X (solenoid), P084X (pressure).

ECM CODES: P0700
TCM CODES:
  P0731  Gear ratio incorrect (1st)
  P0750  Shift solenoid A malfunction
  → Diagnosis: shift solenoid A

Check transmission fluid

On the Ram 1500, the 545RFE has no dipstick on later models — check via the fill plug with engine running and trans at 110°F. Fluid should be clean cherry red. Dark brown or burnt smell = damage already done.

Inspect TCM connector and wiring

Disconnect TCM connector (usually under driver-side dash or on top of trans). Check pins for corrosion, bent terminals, or evidence of moisture. Wiggle-test the trans harness while monitoring live data.

Test individual solenoids

With a bidirectional scanner, command each solenoid on/off. Listen at the trans for a click. Measure resistance at the TCM connector — spec is usually 10–20Ω.

WarningNever drive a transmission with active P0700 + slipping symptoms more than a few miles. You can destroy a $4000 trans saving a $200 tow bill.

Consider a fluid+filter service

On 545RFE/68RFE Ram trucks, a fresh ATF+4 service plus filter often resolves shift quality issues caused by stuck valve body solenoids. Don't flush — drain and refill only.

How to Fix It

DifficultyTime 2–3 hrs

Parts needed:

ATF+4 Transmission Fluid (case, 6 qt) — approx $75
545RFE Shift Solenoid Pack — approx $245
Mopar Transmission Filter Kit — approx $65
Input/Output Speed Sensor — approx $55
TCM (Reman, Mopar) — approx $480

Procedure:

Scan with a transmission-capable tool (not basic OBD-II).
Document all TCM and ECM codes.
Check fluid level and condition at operating temp.
Inspect TCM connector for corrosion.
Perform drain/refill with ATF+4 and new filter.
Clear codes; road test through all gears.
If codes return, isolate to specific solenoid/sensor.
Replace the failed component using factory torque specs.

Will It Pass Emissions?

// DECISION TREE

STARTCheck engine light on?

YES →FAIL

NO →Readiness monitors set?

YES →PASS

NO →RETESTdrive 50–100 miles to set monitors

Repair Cost Breakdown

Part / Region	DIY Cost	Shop Labor	Total Range
Most regions (light DIY)	$140	—	$110–$320
Most regions (shop)	—	$650	$280–$950
Heavy repair (shop)	—	$3400	$2800–$4500

Estimates based on aggregated independent shop quotes; dealer labor adds 30–50%. Excludes diagnostic fee ($80–$150).

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FAQs

It can be. P0700 is just a flag — the real code is in the TCM. Some causes are $50 fixes; others are $4000 rebuilds. You won't know until you read the TCM codes.

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Sources & References

§SAE J2012 — Diagnostic Trouble Code Definitions — Standardized OBD-II code definitions used by all manufacturers.
§EPA OBD Regulations (40 CFR §86.1806-05) — Federal on-board diagnostic requirements for light-duty vehicles.

Cost figures are aggregated from real customer invoices at our shop plus quotes from RepairPal and Mitchell1 labor guides. Diagnostic procedures verified against factory service information (ALLDATA / Mitchell1).

// About the author

Mike Reeves — Independent shop owner in Phoenix, AZ. Specializes in driveability diagnostics on domestic and Asian gas engines. Writes our powertrain coverage. More about our team →

Related Codes

P0420MODERATE