Engine Intake Manifold #1 Pressure — Data Valid But Below Normal (Most Severe)
The DD-102-1 (Detroit Diesel DD Series) diesel fault code means: Engine Intake Manifold #1 Pressure — Data Valid But Below Normal (Most Severe). This is a moderate severity code.
This is a standard J1939 fault, not a proprietary code. DD-102-1 is how this equipment displays SPN 102 with FMI 1 (data valid but below normal — most severe) under the SAE J1939 standard used across heavy equipment. The same SPN can appear on any J1939-compliant machine regardless of brand — so cross-referencing it against your engine maker's documentation is valid even when the equipment brand differs.
- Keep driving?
- Yes, but fix soon
- DIY difficulty
- intermediate
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What Are the Symptoms of DD-102-1?
- Check Engine or an aftertreatment warning light
- A Engine Intake Manifold #1 Pressure reading outside its normal range on the diagnostic software
- Possible derate depending on severity level
What Causes DD-102-1? (Most Likely First)
- The condition the Engine Intake Manifold #1 Pressure parameter measures is genuinely out of range High
- Sensor reading wrong (sensor or wiring) Medium
- A related system fault driving the value out of range Medium
Can I Still Drive with DD-102-1?
Yes, but fix soon. DD-102-1 is rated moderate severity. It is not an immediate stop-driving fault, but it will not clear itself — book the repair rather than ignoring it.
Frequently Asked Questions
What does SPN 102 FMI 1 mean?
SPN 102 is "Engine Intake Manifold #1 Pressure" in the SAE J1939 Digital Annex, and FMI 1 means the measured value is below its normal operating range at the most severe level. Together they say the measured value is below its normal operating range at the most severe level for that parameter.
Is this a Detroit Diesel-specific code?
No. It is a standard J1939 SPN and FMI pair, so the parameter and failure mode mean the same on any J1939 engine. What Detroit Diesel checks before setting it, and what the truck does about it, is in Detroit Diesel service information.
Mechanics Guide Step-by-step diagnosis
How Do You Diagnose DD-102-1?
Read the live Engine Intake Manifold #1 Pressure value and compare it with the expected range for the operating condition.
Compare it with related sensors to decide whether the condition is real or the sensor is wrong.
Follow the manufacturer's procedure for the pair before replacing parts.
Sources 2
This page is built from documented references. Verify against your own service info before repair work.
- SPN 102 record in the ISOBUS Data Dictionary (ISO 11783 online database), reproducing the SAE heavy-duty Digital Annex (DA) name "Engine Intake Manifold #1 Pressure". Establishes what the SPN names, not what a Detroit Diesel display shows for it.ISO 11783 online database copy of the SAE J1939 Digital Annex SPN list — readable, not SAE’s current edition
- SAE J1939-73Application Layer: Diagnostics (defines the SPN/FMI fault-identifier framework)
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