REM Gauge Readouts Summary

Here is a summary of all the available readings that have been programmed into the Renix Engine Monitor.

Renix Engine Readings

MAP = Manifold Absolute Pressure sensor

The MAP sensor reads the absolute (actual) pressure inside the intake manifold.

Note: An Absolute Pressure is not zeroed out, so a lower number means lower pressure.
Remember that the Earth’s Atmospheric Pressure is 29.9”Hg (14.7psi) at Sea Level, so a running engine will read less pressure than the atmosphere.

– Engine Off (~30”Hg at sea level) This should read Atmospheric Pressure
– Engine Idle (< 15”Hg) A healthy engine should pull decent low pressure at idle
– Open Throttle (~15-30″Hg) Opening the throttle should raise the pressure

VAC = Relative Manifold Vacuum.

This gauge calculates the Manifold Relative Vacuum in the intake manifold instead of the Absolute value above. This is a normal vacuum gauge that has been zeroed to the earth’s atmosphere and shows a negative pressure, which we call a vacuum.

Note: This is calculated from the MAP and Baro reading: Vacuum = [Baro] – [MAP]

– Engine Off (~0”hG), The engine should show ~0 vacuum when off
– Engine Idle (> 15”hG) A healthy engine should pull decent vacuum at idle
– Open Throttle (~0-15″Hg) Opening the throttle should lower the vacuum

ºFWT = Water Temperature

Shows Temperature of the Engine Coolant from the Temperature Sender in the lower drivers side of the engine block.

Note: This may read different from the temp gauge in the dash because it is a different sender. The dash sender is located on the rear driver side of the cylinder head.

– Engine Cold (~Outside Air Temp) This should be close to the Ambient Air
– Engine Warm (~180 – 220ºF) 210ºF is proper Engine Operating Temperature

ºFIA = Intake Air Temperature

Shows Temperature of the incoming air inside the Intake Manifold.

– Engine Cold (~Outside Air Temp) This should be close to the Ambient Air
– Engine Warm (~90-130ºF) This reading should be hotter than Ambient Air

RPM = Revolutions Per Minute

Shows how fast the Engine is spinning based off the Crankshaft Position Sensor (CPS)

Note: This reading is actually the spark timing gap that the ECU sends to the ignition module.

– Engine Off (0) There should be no reading when off (may persist after engine stops/stalls)
– Engine Idle (~600-900) Proper Idle should be around 750 RPM
– Engine Redline (5000) Engine speed should not go over 5000 RPM

VLT = Battery Voltage

This displays the current voltage of the Battery.

Note: On 4.0L This may be the Fuel Pump/o2 Circuit which will normally read 0v after 3 seconds when the engine is off. This will read correctly when the engine is running.

– Engine Off (~12.4-12.8) A healthy battery will rest around 12.6 Volts
– Engine Idle (~13.5-14.5) A healthy Alternator should supply 13.5-14.5 Volts

vO2 = Exhaust Gas Oxygen Sensor Voltage

Shows the Oxygen content in the Exhaust Gas Stream reported from the Oxygen Sensor. For proper Closed Loop operation, this reading should constantly swing between a high and low value.

Note: A faulty oxygen sensor will not move at all and usually pegs lean.

4.0L: (0v to 5v signal)
– (< 2.5v) Exhaust is reading RICH, Oxygen content low
– (> 2.5v) Exhaust is reading LEAN, Oxygen content high

2.5L (0mV to 1000mV signal)
– (< 500mV) Exhaust is reading RICH, Oxygen content low
– (> 500mV) Exhaust is reading LEAN, Oxygen content high

EX = Exhaust Gas Status

ECU reported value that Indicates whether the Exhaust is Richer or Leaner than Stoichiometric (14.7lbs of air to 1lb of fuel)

– (LEAN) Exhaust Mix has more Air than 14.7:1
– (RICH) Exhaust Mix has more Fuel than 14.7:1

vHT = Oxygen Sensor Heater Relay Voltage

Shows the Voltage that the Oxygen Sensor Heater Relay is supplying to the Oxygen Sensor. This reading may read 0v under WOT Open Loop Conditions.

Note: This is an REM reading from a built-in Voltage Divider that can safely read from 0 to 18V DC.

– Engine Off (0v) The ECU will provide power for 3 seconds, then stop
– Engine Running (~12-14v) Voltage drop may cause less than battery from the Relay

LP = Exhaust Loop Status

Indicates the Loop Mode that the ECU is currently in. This will read OPEN when the engine is cold and should switch to CLOSED when the oxygen sensor is ready. A faulty o2 reading will prevent closed loop and use more fuel to run.

– (OPEN) ECU Ignores o2 Sensor and runs off a base fuel curve
– (CLSD) ECU uses o2 Sensor to obtain proper air/fuel ratio
– (DECEL) ECU enters fuel cut-off mode during hard Deceleration(>1,200 RPM & Closed TPS)

EGR = Exhaust Gas Recirculation

Displays if the ECU is allowing the EGR Solenoid to open or close the EGR Valve.

– (ON) EGR Valve is Open, usually during Closed Loop
– (OFF) EGR Valve is Closed, usually during Warm-Up, Idle, WOT, and Decel

TPS = Throttle Position Sensor

Shows how far the Throttle Plate is open in Percent.

– Closed (~14-18) The TPS should rest at 17% when closed, adjust if necessary
– Wide Open (~94) The TPS will NOT read up to 100% under normal operation

TH = Throttle Position Mode / Switch

4.0L: Shows what mode the ECU is reading the TPS as.
2.5L: Shows Closed Throttle Switch in the ISM, and a WOT Switch on some models.

– (CLSD) ECU reads TPS as completely closed
– (PART) ECU reads TPS as Partially Open and operates normally
– (WOT) ECU reads TPS as being Wide Open Throttle and will go into Open Loop

IGN = Ignition Timing Advance (ºBTDC)

Shows how much Ignition Advance the ECU is applying in Degrees Before Top Dead Center. Engine Knock will lower this reading.

– Idle (10-20º) Advance is low during Idle
– Throttle (30-40º) Advance will rise with throttle input

KNO = Knock Sensor

Lower Driver Side of Engine Block, sends an electrical signal to the ECU if Engine Knock is measured. This reading will be near 0 at idle and rise with RPM

– Engine Idle (~ 0) No Engine Knock is detected
– Engine 2500 RPM (~10-100) A little knock with RPM increase is normal

mS = Injector Pulse Width (mS)

Shows the length of time the ECU is energizing a fuel injector for in Millisecond which relates to how much actual fuel is being requested.

Note: This will read much lower on 2.5L’s due to a single TB Injector

4.0L:
– Engine Idle (~4-8) Should be low when engine is running properly in closed loop
– Engine Raised RPM (~6-22) Will vary on how much fuel is needed.

2.5L:
– Engine Idle (~1-2) Should be low when engine is running properly in closed loop
– Engine Raised RPM (~2+) Will vary on how much fuel is needed.

%DC = Injector Duty Cycle

This shows the percentage of time the Injector is energized compared to the time it takes the engine to complete one cycle. A properly sized Injector should never be above 80% DC.

– Idle (~2-10%) Low RPM means less fuel and a longer engine cycle
– WOT (< 80%) At Max RPM the Injectors shouldn’t be on for more than 80%

SYN = Distributor Fuel Sync Signal

Reads the sync signal generator in the distributor to determine proper firing order by locating piston 1’s compression stroke. This may not update when engine is off.

Note: Due to the Flywheel only showing piston pairs (1/6, 2/5, 3/4), the sync signal is required to determine which pair is on a compression stroke and set it’s firing order.

– (+) Piston 1 is on Compression Stroke
– (-) Piston 6 is on Compression Stroke

ST = Short Term Fuel Trim (Adaptive Offset)

This is a value used by the ECU to monitor the instantaneous amount of fuel required to run properly. This value is an offset of the LT Fuel Trim and will change with current Engine Conditions.

Note: This value will only update in Closed Loop, otherwise the base value of 128 is shown

– (< 128) The ECU needs less fuel then base to run properly
– (128) The ECU is using the Base Fuel Curve (Open Loop)
– (> 128) The ECU needs more fuel then base to run properly

LT = Long Term Fuel Trim (Adaptive Gain)

This is a value used by the ECU to monitor the average fuel required to run properly. This value doesn’t usually change after the ECU has adapted to the fueling requirements.

Note: If the ECU can not properly hold Closed Loop for an extended period of time, the base value of 128 will not update.

– (< 128) The ECU needs less fuel on average then base to run properly
– (128) The ECU is using the Base Fuel Curve
– (> 128) The ECU needs more fuel on average then base to run properly

A/C = Air Conditioning Select Signal

Displays if the ECU is detecting the A/C Select Signal to activate the A/C Compressor Clutch. The A/C Mode Select Switch and A/C Low Pressure Switch must both be closed for this to be displayed.

– (ON) A/C Select Signal is active
– (OFF) A/C Select Signal is not active

REQ = Air Conditioning Request Signal

Indicates if the A/C Evaporator Thermostat Temperature Switch is at an acceptable range for A/C use.

Note: The A/C Select Signal must be active for the Request Signal to work.

– (YES) All conditions met for A/C operations
– (NO) One or more conditions are not met for A/C operations

ACCL = Air Conditioning Clutch Signal

Indicates if the Air Conditioning Clutch Relay is being requested.

– (ON) A/C Clutch Signal is active
– (OFF) A/C Clutch Signal is not active

GPH/MPG = Current Gallons per Hour / Miles per Gallon

Displays current estimated fuel consumption in Gallons Per Hour. This is estimated from injector flow rate and injector duty cycle.

Note: This is only an estimate, as different injectors and other vehicle conditions will affect this. For accurate readings, the Fill-Up feature should be used for 2 consecutive Full Fill-ups.

On auto trans vehicles, MPH can be used to calculate Miles per Gallon.


AW-4 Auto Trans Readings

RPM = Transmission Output Shaft RPM

Displays the Revolutions per Minute of the transmission output shaft from the Vehicle Speed Sensor(VSS). May not read below 300 RPM.

MPH/KPH = Miles per Hour / Kilometers per Hour

Displays the speed of the vehicle. This is based off the transmission speed sensor (VSS) and calculates speed from Trans RPM and other driveline options.

Note: Vehicle Driveline options must be set for accurate reading. This reading cannot account for transfercase 4-lo range.

0T = Transmission TPS Steps

Displays the Transmission side of the Throttle Position Sensor in Steps from 0 to 7. This is separate from the Engine side of the TPS but should still stay synchronized. This is used by the TCU to modify the shift points to intended driving style.

GEAR = Current Gear

Displays which gear the transmission is currently in. This only shows what gear the TCU has selected and may not accurately reflect custom bypass shifters.

PRND = Shifter Selection

Displays whether the Transmission Range Shifter is in a normal position (PRND) or a manual mode such as (3RD) or (1-2).

B12LC0T = Combination Trans Info Gauge

This is a combination gauge that displays most of the TCU gauges in one line. Readings will display on the screen when they are currently active.

– (B) = Brake Switch
– (1,2,L) = Solenoids
– (C/P) = Comfort/Power Switch
– (0T) = Trans TPS in steps.

 0/0 = TCU Error Codes

The AW-4 TCU has the ability to throw basic trouble codes. The first number is for Solenoid Codes and the second is for TPS Codes. Under the AW-4 TCU Menu, the right selection buttons will bring up TCU Error Screen and display current and stored codes.

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