5.6 Keyless Ignition System¶
Push-button ignition for the Cummins R2.8 + 8HP70 build. Replaces the factory keyswitch entirely. Self-contained Digital Guard Dawg PBS-I handles RFID immobilizer, brake interlock, and ACC/IGN/START sequencing internally. One external SPST relay gates cranking through the diesel wait-to-start lamp so cold-day starts auto-wait for grid heater preheat. PMU is not involved.
Architecture¶
Module: Digital Guard Dawg PBS-I (Intelligent Push Button Start)
Type: Self-contained RFID push-button start/stop; onboard 60A relays (IGN, START, ACC1, ACC2)
Mounting: Cabin, under dash (vendor mandate: not in engine bay)
Product Page: Digital Guard Dawg PBS-I
Install Manual: PBS-I Manual PDF
Components¶
Digital Guard Dawg PBS-I¶
| Specification | Value |
|---|---|
| Type | RFID push-button start, self-contained |
| Onboard Relays | 4× 60A1 (IGN, START, ACC1 drops during crank, ACC2 stays on during crank) |
| Inrush Capacity | 300A1 |
| Supply Voltage | 12V DC |
| Detection Range | ~10 ft (iTag fob) |
| Auto-arm | 60 sec after fob leaves range |
| Module Dimensions | ~5.5" × 3" × 1.25" |
| Wiring | Heavy-duty Molex high-current connectors, 12 GA bus wiring |
| Mounting | Cabin, under dash (vendor mandate: do NOT mount in engine bay) |
| Kit Contents | ICM + 2 iTag fobs + Start Button (36" pre-wired harness) + Programming Button + Bypass Card + 4-digit PIN |
WAIT-gate Relay¶
Single SPST automotive relay with normally-closed contacts. Blocks PBS-I's START output from reaching the Cole Hersee coil while the Cummins WAIT-to-Start lamp is illuminated.
The Cummins R2.8 ECM uses a sink-circuit lamp topology: keyswitch +12V → lamp → ECM Pin 35 (yellow) → ECM internal sink to ground when condition is active. The WAIT signal at Pin 35 is therefore active LOW (~0V when WAIT lamp on, ~+12V when WAIT lamp off).5
| Specification | Value |
|---|---|
| Type | 5-pin SPDT changeover, used as SPST-NC (30/87a wired, 87 unused); 30A NO / 20A NC contacts2 |
| Coil | 12V DC, ~160 mA |
| Coil+ | Switched +12V (tap from ignition signal bus bar — same source as the WAIT lamp itself) |
| Coil- | ECM Pin 35 (yellow WAIT-to-Start wire) tap on cabin side (shared with HDX WAIT/EX input) |
| Contacts | NC (87a); closed when coil de-energized (WAIT lamp off), opens when coil energized (WAIT lamp on) |
| Mounting | Cabin, adjacent to PBS-I |
| Part | Bosch 0332209150 (superseded by 0986332400) — 5-pin changeover2 |
Cole Hersee 24213 Solenoid¶
Unchanged from existing starter design. See Starter System.
Daily Start Sequence¶
Warm engine (no preheat cycle):
- Approach vehicle — iTag fob in pocket — Start Button LED illuminates
- Press brake pedal — Start Button LED begins flashing
- Press and hold Start Button — starter cranks immediately, release on engine start
Cold engine (grid heater active):
- Approach — fob recognized — Start Button LED illuminates
- Press brake + press and hold Start Button
- PBS-I energizes PINK IGN immediately → ECM powers up → grid heater runs → WAIT-to-Start lamp illuminates
- PBS-I asserts PURPLE START, but WAIT-gate relay holds it open while WAIT lamp on — keep holding button
- ~3-5 seconds later (per Grid Heater), WAIT lamp extinguishes → WAIT-gate relay NC closes → starter cranks
- Release on engine start
Shut off: Press brake + press and hold Start Button for 2 seconds.
Accessory-only mode (e.g., radio without engine): press button once without brake — ACC2 energizes. Second press adds ACC1 + IGN.
Emergency bypass (lost or damaged fob): Use Programming Button + 4-digit PIN from the Bypass Card stored in wallet. See PBS-I Manual.
Wiring¶
PBS-I Power Harness (6 wires)¶
| Wire | Function | Source | Destination | Notes |
|---|---|---|---|---|
| RED | +12V Battery | Critical Cabin PDU (CONSTANT) | PBS-I module | 14 AWG; ~50 mA standby (TBD verify) |
| BLACK | Chassis Ground | Cabin ground bus | PBS-I module | 14 AWG |
| PINK | 1st Ignition Out (60A) | PBS-I module | Ignition signal bus bar (cabin), Stud 1 | Does NOT drop during crank; bus bar Stud 2 outbounds to ECM Pin 41 via 5A inline fuse4 |
| PURPLE | Starter Out (60A) | PBS-I module | WAIT-gate relay common (NC input) | Cranks while button held |
| PINK/BLK | Accessory 1 (60A) | PBS-I module | [Reserve] | Drops during crank |
| BROWN | Accessory 2 (60A) | PBS-I module | [Reserve] | Stays on during crank |
PBS-I Accessory Harness (2 wires used)¶
| Wire | Function | Source | Destination | Notes |
|---|---|---|---|---|
| BROWN | Brake (+) input | Stop-lamp switch cold side | PBS-I Brake input | T-tap shared with PMU In 2 and Turbolamik brake input |
| PURPLE | Ground upon Disarm | PBS-I module | [Reserve] | Active-low fob-present signal; available for future use |
Start and Programming Buttons¶
| Connector | Connection | Notes |
|---|---|---|
| Start Button | Pre-wired 36" harness → PBS-I side port | Dash mount; included in kit |
| Programming Button | Pre-wired harness → PBS-I side port | Stash under dash or in trunk; needed only for fob-learn and emergency bypass PIN entry |
WAIT-Gate Relay¶
| Wire | Source | Destination | Notes |
|---|---|---|---|
| Coil (+) | Switched +12V tap (ignition signal bus bar terminal) | WAIT-gate relay coil+ | Same source that powers the WAIT lamp |
| Coil (-) | WAIT-gate relay coil- | T-tap on ECM Pin 35 wire (cabin side, shared with HDX WAIT/EX input) | Active-low sink path; ECM grounds this wire when WAIT lamp on |
| Contact COM | PBS-I PURPLE START | WAIT-gate relay COM terminal | |
| Contact NC | WAIT-gate relay NC terminal | Firewall Pin 15 → Cole Hersee 24213 coil+ | Closed when WAIT off; opens when WAIT on |
See HDX Control for the existing WAIT/EX wiring on the cabin side.
Firewall Crossings¶
Two PBS-I outputs need to cross the firewall from cabin (PBS-I location) to engine bay:
| Signal | Direction | Approximate Current | Notes |
|---|---|---|---|
| Ignition signal (outbound from cabin bus bar) | Cabin → EB (HDP24 Pin 12) | ~5A typical (ECM + PMU Pin 7) | 14 AWG; feeds ECM Pin 41 (black, via 5A inline fuse4) and PMU Pin 7 |
| WAIT-gated PURPLE | Cabin → EB (HDP24 Pin 15) | ~0.69A (Cole Hersee coil)3 | 16 AWG sufficient; drives Cole Hersee 24213 coil+ during crank only |
See Firewall Ingress for pin assignments.
Why Not the Engine-Running Lockout or P/N Interlock Relay?¶
Earlier iterations of this design included a discrete engine-running lockout relay and a P/N interlock relay in series with the starter coil. Both were removed in favor of simpler, layered protection:
- Brake interlock is built into PBS-I (Accessory Harness Brake input).
- Engine-running protection relies on the starter's Bendix overrunning clutch plus the deliberate brake + button-hold required to crank — accidental restart of a running engine takes two-handed misuse.
- P/N interlock is provided by the 8HP70 + Turbolamik: the transmission can't leave Park without brake pressed, and the vehicle is always in Park at start time. The Turbolamik P/N aux output can inhibit the start signal in a future phase if needed (documented, unused today).
Diesel Runaway Note¶
Normal engine shutdown (press brake + 2 sec button hold) drops PBS-I's PINK IGN output, cutting ECM power. However, ECM-only kill does not stop a runaway sustained by oil or hydrocarbon vapor. Independent mechanical protection is provided by the Mishimoto catch can (prevention) plus the AMOT 4261M air shutoff valve with dash-mounted manual cable (termination). See Diesel Runaway Protection.
Outstanding Items¶
- Confirm the WAIT-gate relay coil (~150 mA) in parallel with the dash WAIT lamp does not exceed the ECM lamp-driver sink rating (Pin 35 polarity itself is confirmed active-low per Cummins 5504137 — see 5). If marginal, drive the relay from the lamp's keyswitch side or use a higher-impedance/solid-state relay
- Order Digital Guard Dawg PBS-I kit (includes ICM, 2 fobs, Start Button, Programming Button, Bypass Card, harnesses)
- ~~Select WAIT-gate relay part~~ → Bosch 0332209150 (5-pin SPDT changeover, superseded by 0986332400); wire COM (30) + NC (87a), leave NO (87) open. See 2.
- Add 5A inline fuse on the ignition (keyswitch) feed to ECM Pin 41 — pink wire, per Cummins 5504137 (see 4)
- Select PBS-I module mounting location (cabin under-dash, away from heat and water)
- Select Start Button dash mounting position (within easy reach of driver)
- Select Programming Button storage location (hidden but accessible)
- Verify PBS-I quiescent current draw to add to START battery parasitic budget
- ~~Confirm Feature Programming defaults~~ → PBS-I has no DIP/jumper menu; shipped Feature Programming defaults confirmed acceptable for this build (no reprogramming required at install). Owner decision, 2026-06-03.
Related Documentation¶
- Starter System - Cole Hersee 24213 and PBS-I PURPLE → WAIT-gate → coil chain
- Ignition Signal Distribution - PBS-I PINK IGN feeds the bus bar
- HDX Control - WAIT/EX signal source for the gate relay
- Grid Heater System - R2.8 grid heater duty cycle (3-5 sec typical)
- Firewall Ingress - PBS-I pin assignments
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Onboard relay ratings (4× 60A), 300A inrush capacity, and kit contents per the Digital Guard Dawg PBS-I install manual (PBS-I Manual PDF) and product page (Digital Guard Dawg PBS-I). ↩↩
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Bosch 0332209150 — 5-pin SPDT changeover mini-relay, 12V, 30A NO / 20A NC, ~160 mA coil (Bosch/Amazon listing, accessed 2026-06-03; superseded by 0986332400). This circuit energizes the coil to open the start path (WAIT lamp on → coil energized → contacts open), so it must use the NC (87a) contact — which requires a changeover relay. The earlier "suggested" parts were both wrong for this: Bosch 0332019150 is a twin-87 NO-only relay (no 87a terminal) and Hella 4RA is an SPST make-only series — neither has an NC contact. The NC side here carries only the Cole Hersee 24213 coil (~0.69A), far under the 20A NC rating. Equivalent changeover relays (Hella 4RD series, Tyco/TE V23234) are acceptable substitutes. ↩↩↩
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Cole Hersee 24213 coil draw ~0.69A (17.5 Ω @ 12V) per the Littelfuse datasheet — see the
[^ch-24213]footnote in Starter System. Supersedes the earlier unsourced "~1.6A" figure that appeared in pre-merge drafts. ↩ -
Confirmed. Cummins Repower R2.8 CM2220 R101B Installation Guide, Bulletin 5504137 (Jan 2018), §2 Wiring Harness (pp. 2-19/2-20): the keyswitch feed to the ECM is Pink, ECM pin 41, with a 5 amp inline fuse (Figure 2, item 3: "Keyswitch – pink, 5 amp inline fuse"). The guide requires this "pink 5 amp wire … provide a minimum of 12 volts in the run position and during engine cranking." Supersedes the unverified "document 0042728" cited in pre-merge drafts. ↩↩↩
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Confirmed active-low. Cummins Repower R2.8 CM2220 R101B Installation Guide, Bulletin 5504137 (Jan 2018), §2 Wiring Harness / Engine Indicator Lamps (pp. 2-19 → 2-24): the Circuit Wiring table lists Lamp, Wait To Start — Yellow — ECM pin 35, and the guide states "The lamp circuits require power from the keyswitch to each lamp, with the ECM providing a path to ground via a sink circuit as engine conditions dictate" and "The ECM will enable a grounding path for the warning light to illuminate." Pin 35 is therefore active-low (ECM sinks to ground when WAIT is active), validating the WAIT-gate relay logic above. The full schematic is the separate R2.8 CM2220 R101B Wiring Diagram, Bulletin 5467560 (QuickServe Online). Supersedes the unverified "document 0042728" cited in pre-merge drafts. Note: the relay taps ECM Pin 35 directly, so it is governed by this Cummins spec — independent of the HDX cluster-input polarity question in HDX Control. ↩↩