Mode Seven pending codes are the results of a standard OBD-II scan-tool request, officially Service $07, that asks the engine computer for emissions faults detected during the current or last completed drive cycle. It is the tool-side window into faults that have been seen but not yet confirmed.
This article focuses on the service itself: what the scan tool asks for, what the vehicle sends back, how different tools present the answer, and how technicians and DIYers use it as a quick check after repairs. If you want the basics of what a pending code is, a separate guide covers that topic.
The Question Your Scan Tool Is Really Asking
OBD-II scan tools do not browse the car’s computer freely. They send standardized requests, called services or modes, defined in the SAE J1979 standard. Each service asks a specific question, such as what the live data is, what codes are stored, or what codes were seen recently.
Service $07 asks the second of those questions in a narrow form: which emissions-related trouble codes were detected during the current or last completed drive cycle? A drive cycle, in this sense, is a period of operation from engine start through shutdown that allows the relevant monitors to run.
The answer is a list of codes, or a report that none were found. Because the request is standard, any OBD-II compliant scan tool can send it to any compliant vehicle, regardless of brand, as long as the tool offers the function in its menu.
Where Mode Seven Fits Among the Other Services
OBD-II defines ten diagnostic services, numbered $01 through $0A. Mode 7 is easiest to understand when you see the neighbors it works with during a normal diagnosis.
Service $01 reads live data and readiness status. Service $02 reads freeze frame data, the snapshot of conditions saved with a confirmed fault. Service $03 reads confirmed, or stored, codes. Service $04 clears codes and resets monitors, and Service $0A reads permanent codes on vehicles that support them.
Mode 7 sits beside Mode 3 as a companion. Mode 3 tells you what has been verified and has usually turned on the check engine light. Mode 7 tells you what the monitors noticed most recently, whether or not it has matured. Reading both gives a much fuller picture of current emissions faults.
How to Request Mode Seven on Most Scan Tools
The menu names differ between tools, but the process is similar on almost all generic OBD-II readers. Work with the vehicle parked, the parking brake set and the transmission in park or neutral.
- Locate the 16-pin diagnostic connector, usually under the dashboard on the driver’s side.
- Plug in the scan tool with the ignition off, then switch the ignition on or start the engine outdoors.
- Let the tool establish communication and identify the protocol automatically.
- Open the codes menu and choose the option labeled pending codes, Mode 7 or Service $07.
- Record every code shown, along with any message that no pending codes were found.
Some tools read all code types in one step and label each result. Others need a separate selection. If your tool has no visible pending option, check its manual before concluding that it cannot read Mode 7.
Reading the Answer the Vehicle Sends Back
The vehicle’s response to a Mode 7 request is simple, but a few details help you interpret it correctly.
One List or Several
On newer vehicles using the CAN protocol, required on US vehicles from model year 2008, more than one control module may answer. The engine computer and a separate transmission computer can each report pending emissions codes.
Better scan tools show which module sent each code. That detail helps when the same symptom could come from either system.
Codes That Also Appear in Mode 3
The same code can appear in both the pending and confirmed lists. This usually means the fault was already confirmed and was detected again during the most recent drive cycle.
A code in both lists after a repair is a strong sign that the fault is still present and needs further testing.
An Empty Pending List
No pending codes means no emissions fault was detected in the current or last completed drive cycle. It does not prove that every monitor ran.
Check readiness status through Mode 1. If a monitor has not completed, it has not had the chance to report a pending failure yet, so an empty list says little about that system.
Why Technicians Rely on Mode Seven After Repairs
After a repair, the slow part of verification is waiting for the check engine light to stay off. Confirmed codes may take more than one trip to reappear. Mode 7 shortens that wait because it shows a failure from the very first drive cycle in which the monitor runs again.
A typical approach is to repair the fault, clear codes if appropriate, and then drive under conditions that let the related monitor run. Afterward, a Mode 7 check shows whether the monitor has already detected the fault again, often before the lamp would come back on.
This makes Mode 7 one of the most practical services for DIYers as well. A clean pending list after the monitor has completed is good evidence that the repair worked. A returning pending code means more testing is needed before the next inspection.
Timing Your Mode Seven Checks
When you run Mode 7 matters. Because it reports the current or last completed drive cycle, checking right after a cold start can show a different picture than checking after a long drive. Some monitors need extended steady cruising or specific temperatures before they run.
For repair verification, scan after a drive that includes a cold start, gradual warm-up, city driving and a period of steady highway speed. The exact enabling conditions for each monitor are listed in the service manual and vary by manufacturer and model.
Never perform the scan or watch data while driving. Pull over safely and park first, or have a passenger operate the tool. If you need to let the engine idle during the check, do it outdoors or in a well-ventilated space.
Limits of What Mode Seven Can Show
Mode 7 is powerful within its scope, but it has clear boundaries. Knowing them prevents false confidence in a clean result.
- It reports emissions-related codes only, not airbag, anti-lock brake, body or most network faults.
- It cannot show faults from monitors that have not run during the current or last completed drive cycle.
- It does not return freeze frame data; that snapshot is read separately through Mode 2.
- It is erased by Mode 4 clearing, along with stored codes and readiness results.
For non-emissions modules, an enhanced scan tool that reads manufacturer-specific data is needed. For airbag systems, diagnosis and repair should be left to a qualified technician, since probing those circuits can cause accidental deployment.
Pairing Mode Seven With Mode Six Test Results
Service $06 reports the actual results of individual on-board monitor tests, along with the limits the computer used to judge them. Mode 7 tells you that a monitor failed. Mode 6 can show how close a test came to its limit, even when it passed.
Together, they help with borderline faults. A monitor that passes in Mode 6 but sits near its limit may soon produce a pending code. A Mode 7 code combined with a clear Mode 6 failure confirms which test is involved and narrows the search.
Mode 6 data is less user-friendly on some tools and can require a service manual to interpret. If your tool displays it, use it as supporting evidence. If not, Mode 7 combined with readiness status still gives a reliable early signal.
Common Misreadings of Mode Seven Results
Some owners treat a pending code as proof that a part is bad. The code identifies what a monitor saw, such as a lean condition or an evaporative leak, not which component failed. Test the system before replacing anything.
Others assume a pending code that disappears was a scan-tool error. In reality, pending codes are designed to drop away when the fault does not repeat. A code that keeps returning across several scans deserves attention even if it never matures.
A third mistake is clearing pending codes to make the list look clean before an inspection. This also resets readiness monitors and erases stored data. Many state emissions programs check readiness, so the shortcut often causes a failed or rejected test instead.
Making Mode Seven Part of Every Scan
Mode Seven pending codes are most useful when you check them routinely, not only after a warning light. Adding a pending code check to every scan gives early notice of developing faults and fast feedback on repairs.
Pair the result with readiness status and the confirmed code list, then record everything in a simple log. That combination shows what the car has seen recently, what it has verified and which monitors still need to run.
When a pending code points to a system you cannot test safely or confidently, consult the service manual or a qualified technician. Bring your scan notes, because a clear record of when Mode 7 codes appeared often makes professional diagnosis faster and more accurate.